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  • Fast Pitches (usually 85mph+ in the major leagues):

    • No Break - Four-Seam Fastball (speed is usually mid to high 90s, can exceed 100, and will appear to head pretty directly to the plate)
    • Breaks Low - Splitter (speed's in the high 80s to low 90s, designed to look like a fastball but takes a dive under the bat; giveaway is a "snappy", compact delivery with the pitcher's index and middle fingers split severely)
    • Breaks Inside - Two-Seam Fastball/Sinker (again, speed in the high 80s/low 90s, designed to look like a fastball but breaks towards a RHB to jam him up)
    • Breaks Outside - Cutter (speed in the low 90s, breaks outside without dropping to look like a four-seam fastball, notorious for breaking bats, difficult to throw correctly and so rare)
    • Breaks Outside Low - Slider (Speed high 80s low 90s, breaks outside and drops to make the batter "chase" what he thought was a four-seam; more often seen than the cutter)
  • Off-speed pitchesOff-speed pitches (between 70-85mph)

    • No Break - Change-up (designed to throw off a batter's timing, looks like a fastball and goes right down the middle, but speed can be as low as 70mph, but more likely high 70s-low 80s)
    • Breaks Low - Forkball (slightly faster than most other off-speed pitches, usually mid-80s, it's quite literally a slow splitter)
    • Breaks Very Low - Curveball (changes everything about the batter's approach, looks like a change-up but dives under the bat. Sometimes incorrectly called a changeup, but the vertical curve is more pronounced. Thrown incorrectly, it doesn't dive, and coupled with the slower speed it's a batter's dream pitch)
    • Breaks Inside - Circle Changeup (Simple variation of the changeup, looks like a change-up but breaks inside much like a two-seam does in the fast pitches)
    • Breaks Inside Low - Screwball (difficult and rare, it looks like a curveball coming in but breaks inside)
    • Breaks Outside Low - Slurve (combination slider/curve, looks like a curveball but breaks outside like a slider)
  • Fast Pitches (usually 85mph+ in the major leagues):

    • No Break - Four-Seam Fastball (speed is usually mid to high 90s, can exceed 100, and will appear to head pretty directly to the plate)
    • Breaks Low - Splitter (speed's in the high 80s to low 90s, designed to look like a fastball but takes a dive under the bat; giveaway is a "snappy", compact delivery with the pitcher's index and middle fingers split severely)
    • Breaks Inside - Two-Seam Fastball/Sinker (again, speed in the high 80s/low 90s, designed to look like a fastball but breaks towards a RHB to jam him up)
    • Breaks Outside - Cutter (speed in the low 90s, breaks outside without dropping to look like a four-seam fastball, notorious for breaking bats, difficult to throw correctly and so rare)
    • Breaks Outside Low - Slider (Speed high 80s low 90s, breaks outside and drops to make the batter "chase" what he thought was a four-seam; more often seen than the cutter)
  • Off-speed pitches (between 70-85mph)

    • No Break - Change-up (designed to throw off a batter's timing, looks like a fastball and goes right down the middle, but speed can be as low as 70mph, but more likely high 70s-low 80s)
    • Breaks Low - Forkball (slightly faster than most other off-speed pitches, usually mid-80s, it's quite literally a slow splitter)
    • Breaks Very Low - Curveball (changes everything about the batter's approach, looks like a change-up but dives under the bat. Sometimes incorrectly called a changeup, but the vertical curve is more pronounced. Thrown incorrectly, it doesn't dive, and coupled with the slower speed it's a batter's dream pitch)
    • Breaks Inside - Circle Changeup (Simple variation of the changeup, looks like a change-up but breaks inside much like a two-seam does in the fast pitches)
    • Breaks Inside Low - Screwball (difficult and rare, it looks like a curveball coming in but breaks inside)
    • Breaks Outside Low - Slurve (combination slider/curve, looks like a curveball but breaks outside like a slider)
  • Fast Pitches (usually 85mph+ in the major leagues):

    • No Break - Four-Seam Fastball (speed is usually mid to high 90s, can exceed 100, and will appear to head pretty directly to the plate)
    • Breaks Low - Splitter (speed's in the high 80s to low 90s, designed to look like a fastball but takes a dive under the bat; giveaway is a "snappy", compact delivery with the pitcher's index and middle fingers split severely)
    • Breaks Inside - Two-Seam Fastball/Sinker (again, speed in the high 80s/low 90s, designed to look like a fastball but breaks towards a RHB to jam him up)
    • Breaks Outside - Cutter (speed in the low 90s, breaks outside without dropping to look like a four-seam fastball, notorious for breaking bats, difficult to throw correctly and so rare)
    • Breaks Outside Low - Slider (Speed high 80s low 90s, breaks outside and drops to make the batter "chase" what he thought was a four-seam; more often seen than the cutter)
  • Off-speed pitches (between 70-85mph)

    • No Break - Change-up (designed to throw off a batter's timing, looks like a fastball and goes right down the middle, but speed can be as low as 70mph, but more likely high 70s-low 80s)
    • Breaks Low - Forkball (slightly faster than most other off-speed pitches, usually mid-80s, it's quite literally a slow splitter)
    • Breaks Very Low - Curveball (changes everything about the batter's approach, looks like a change-up but dives under the bat. Sometimes incorrectly called a changeup, but the vertical curve is more pronounced. Thrown incorrectly, it doesn't dive, and coupled with the slower speed it's a batter's dream pitch)
    • Breaks Inside - Circle Changeup (Simple variation of the changeup, looks like a change-up but breaks inside much like a two-seam does in the fast pitches)
    • Breaks Inside Low - Screwball (difficult and rare, it looks like a curveball coming in but breaks inside)
    • Breaks Outside Low - Slurve (combination slider/curve, looks like a curveball but breaks outside like a slider)
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  • Fast PitchesFast Pitches (usually 85mph+ in the major leagues):

    • No BreakNo Break - Four-Seam Fastball (speed is usually mid to high 90s, can exceed 100, and will appear to head pretty directly to the plate)
    • Breaks LowBreaks Low - Splitter (speed's in the high 80s to low 90s, designed to look like a fastball but takes a dive under the bat; giveaway is a "snappy", compact delivery with the pitcher's index and middle fingers split severely)
    • Breaks InsideBreaks Inside - Two-Seam Fastball/Sinker (again, speed in the high 80s/low 90s, designed to look like a fastball but breaks towards a RHB to jam him up)
    • Breaks OutsideBreaks Outside - Cutter (speed in the low 90s, breaks outside without dropping to look like a four-seam fastball, notorious for breaking bats, difficult to throw correctly and so rare)
    • Breaks Outside LowBreaks Outside Low - Slider (Speed high 80s low 90s, breaks outside and drops to make the batter "chase" what he thought was a four-seamseam; more often seen than the cutter)
  • Off-speed pitches (between 70-85mph)

    • No BreakNo Break - Change-up (designed to throw off a batter's timing, looks like a fastball and goes right down the middle, but speed can be as low as 70mph, but more likely high 70s-low 80s)
    • Breaks LowBreaks Low - Forkball (slightly faster than most other off-speed pitches, usually mid-80s, it's quite literally a slow splitter)
    • Breaks Very LowBreaks Very Low - Curveball (changes everything about the batter's approach, looks like a change-up but dives under the bat. Sometimes incorrectly called a changeup, but the vertical curve is more pronounced. Thrown incorrectly, it doesn't dive, and coupled with the slower speed it's a batter's dream pitch)
    • Breaks InsideBreaks Inside - Circle Changeup (Simple variation of the changeup, looks like a change-up but breaks inside much like a two-seam does in the fast pitches)
    • Breaks Inside LowBreaks Inside Low - Screwball (difficult to throw accuratelyand rare, it looks like a curveball coming in but breaks inside)
    • Breaks Outside LowBreaks Outside Low - Slurve (combination slider/curve, looks like a curveball but breaks outside like a slider)

The variation of speed and breaking action produces a host of possibilities, which a good battery can use to keep the batter guessing. A pitcher can also aim pitches differently to make them look like other pitches; a pitcher can throw a fastball high and fool the batter into thinking it was going to be a sinker or splitter, or can throw a two-seam wide and the batter may think it's an errant four-seam until it breaks back over the plate. 

Batters like a variety of different pitches; exactly what the batter likes should be known by the pitcher and/or catcher, and a combination of what the batter flat doesn't like, and pitches that look like what he does like but then change, are generally the order of the day. From time to time a pitcher may give a batter exactly what he wants, hopefully when he's least expecting it; this is often necessary to avoid showing the batter the same pitch too many times, and a missed opportunity can also put the batter "on the tilt", throwing off their concentration as they mentally kick themselves.

  • Fast Pitches (usually 85mph+ in the major leagues):

    • No Break - Four-Seam Fastball (speed is usually mid to high 90s, can exceed 100, and will appear to head pretty directly to the plate)
    • Breaks Low - Splitter (speed's in the high 80s to low 90s, designed to look like a fastball but takes a dive under the bat; giveaway is a "snappy", compact delivery with the pitcher's index and middle fingers split severely)
    • Breaks Inside - Two-Seam Fastball/Sinker (again, speed in the high 80s/low 90s, designed to look like a fastball but breaks towards a RHB to jam him up)
    • Breaks Outside - Cutter (speed in the low 90s, breaks outside without dropping to look like a four-seam fastball, notorious for breaking bats)
    • Breaks Outside Low - Slider (Speed high 80s low 90s, breaks outside and drops to make the batter "chase" what he thought was a four-seam)
  • Off-speed pitches (between 70-85mph)

    • No Break - Change-up (designed to throw off a batter's timing, looks like a fastball and goes right down the middle, but speed can be as low as 70mph, but more likely high 70s-low 80s)
    • Breaks Low - Forkball (slightly faster than most other off-speed pitches, usually mid-80s, it's quite literally a slow splitter)
    • Breaks Very Low - Curveball (changes everything about the batter's approach, looks like a change-up but dives under the bat. Sometimes incorrectly called a changeup, but the vertical curve is more pronounced. Thrown incorrectly, it doesn't dive, and coupled with the slower speed it's a batter's dream pitch)
    • Breaks Inside - Circle Changeup (Simple variation of the changeup, looks like a change-up but breaks inside much like a two-seam does in the fast pitches)
    • Breaks Inside Low - Screwball (difficult to throw accurately, it looks like a curveball coming in but breaks inside)
    • Breaks Outside Low - Slurve (combination slider/curve, looks like a curveball but breaks outside like a slider)

The variation of speed and breaking action produces a host of possibilities, which a good battery can use to keep the batter guessing. Batters like a variety of different pitches; exactly what the batter likes should be known by the pitcher and/or catcher, and a combination of what the batter flat doesn't like, and pitches that look like what he does like but then change, are generally the order of the day. From time to time a pitcher may give a batter exactly what he wants, hopefully when he's least expecting it; this is often necessary to avoid showing the batter the same pitch too many times, and a missed opportunity can also put the batter "on the tilt", throwing off their concentration as they mentally kick themselves.

  • Fast Pitches (usually 85mph+ in the major leagues):

    • No Break - Four-Seam Fastball (speed is usually mid to high 90s, can exceed 100, and will appear to head pretty directly to the plate)
    • Breaks Low - Splitter (speed's in the high 80s to low 90s, designed to look like a fastball but takes a dive under the bat; giveaway is a "snappy", compact delivery with the pitcher's index and middle fingers split severely)
    • Breaks Inside - Two-Seam Fastball/Sinker (again, speed in the high 80s/low 90s, designed to look like a fastball but breaks towards a RHB to jam him up)
    • Breaks Outside - Cutter (speed in the low 90s, breaks outside without dropping to look like a four-seam fastball, notorious for breaking bats, difficult to throw correctly and so rare)
    • Breaks Outside Low - Slider (Speed high 80s low 90s, breaks outside and drops to make the batter "chase" what he thought was a four-seam; more often seen than the cutter)
  • Off-speed pitches (between 70-85mph)

    • No Break - Change-up (designed to throw off a batter's timing, looks like a fastball and goes right down the middle, but speed can be as low as 70mph, but more likely high 70s-low 80s)
    • Breaks Low - Forkball (slightly faster than most other off-speed pitches, usually mid-80s, it's quite literally a slow splitter)
    • Breaks Very Low - Curveball (changes everything about the batter's approach, looks like a change-up but dives under the bat. Sometimes incorrectly called a changeup, but the vertical curve is more pronounced. Thrown incorrectly, it doesn't dive, and coupled with the slower speed it's a batter's dream pitch)
    • Breaks Inside - Circle Changeup (Simple variation of the changeup, looks like a change-up but breaks inside much like a two-seam does in the fast pitches)
    • Breaks Inside Low - Screwball (difficult and rare, it looks like a curveball coming in but breaks inside)
    • Breaks Outside Low - Slurve (combination slider/curve, looks like a curveball but breaks outside like a slider)

The variation of speed and breaking action produces a host of possibilities, which a good battery can use to keep the batter guessing. A pitcher can also aim pitches differently to make them look like other pitches; a pitcher can throw a fastball high and fool the batter into thinking it was going to be a sinker or splitter, or can throw a two-seam wide and the batter may think it's an errant four-seam until it breaks back over the plate. 

Batters like a variety of different pitches; exactly what the batter likes should be known by the pitcher and/or catcher, and a combination of what the batter flat doesn't like, and pitches that look like what he does like but then change, are generally the order of the day. From time to time a pitcher may give a batter exactly what he wants, hopefully when he's least expecting it; this is often necessary to avoid showing the batter the same pitch too many times, and a missed opportunity can also put the batter "on the tilt", throwing off their concentration as they mentally kick themselves.

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You're not alone; sometimes even the commentators, who have the same "over-the-shoulder" long-lens view that the folks at home do, will simply refer to a pitch as a "breaking ball" if it drops sharply or curves outside, even though a number of specific pitches can do that.

The fundamental theory of pitching is that the batter gains an advantage over the pitcher proportional to his ability to predict the pitcher's next move, and conversely, the pitcher gains an advantage over the batter inversely proportional to the batter's ability to predict the next pitch. Your better pitchers have a number of weapons to accomplish this, but key to all of them is control over three elements of the pitch; speed (and thus timing), vertical axis (drop), and horizontal axis (slide).

From the very good diagram Dor linked to, here's a basic breakdown of the most common RHP's pitches as seen by a RHB:

  • Fast Pitches (usually 85mph+ in the major leagues):

    • No Break - Four-Seam Fastball (speed is usually mid to high 90s, can exceed 100, and will appear to head pretty directly to the plate)
    • Breaks Low - Splitter (speed's in the high 80s to low 90s, designed to look like a fastball but takes a dive under the bat; giveaway is a "snappy", compact delivery with the pitcher's index and middle fingers split severely)
    • Breaks Inside - Two-Seam Fastball/Sinker (again, speed in the high 80s/low 90s, designed to look like a fastball but breaks towards a RHB to jam him up)
    • Breaks Outside - Cutter (speed in the low 90s, breaks outside without dropping to look like a four-seam fastball, notorious for breaking bats)
    • Breaks Outside Low - Slider (Speed high 80s low 90s, breaks outside and drops to make the batter "chase" what he thought was a four-seam)
  • Off-speed pitches (between 70-85mph)

    • No Break - Change-up (designed to throw off a batter's timing, looks like a fastball and goes right down the middle, but speed can be as low as 70mph, but more likely high 70s-low 80s)
    • Breaks Low - Forkball (slightly faster than most other off-speed pitches, usually mid-80s, it's quite literally a slow splitter)
    • Breaks Very Low - Curveball (changes everything about the batter's approach, looks like a change-up but dives under the bat. Sometimes incorrectly called a changeup, but the vertical curve is more pronounced. Thrown incorrectly, it doesn't dive, and coupled with the slower speed it's a batter's dream pitch)
    • Breaks Inside - Circle Changeup (Simple variation of the changeup, looks like a change-up but breaks inside much like a two-seam does in the fast pitches)
    • Breaks Inside Low - Screwball (difficult to throw accurately, it looks like a curveball coming in but breaks inside)
    • Breaks Outside Low - Slurve (combination slider/curve, looks like a curveball but breaks outside like a slider)

The variation of speed and breaking action produces a host of possibilities, which a good battery can use to keep the batter guessing. Batters like a variety of different pitches; exactly what the batter likes should be known by the pitcher and/or catcher, and a combination of what the batter flat doesn't like, and pitches that look like what he does like but then change, are generally the order of the day. From time to time a pitcher may give a batter exactly what he wants, hopefully when he's least expecting it; this is often necessary to avoid showing the batter the same pitch too many times, and a missed opportunity can also put the batter "on the tilt", throwing off their concentration as they mentally kick themselves.