In American football, purpose of motioning the slot receiver

Question

While watching a play with the New England Patriots you often see the z receiver or slot receiver (correct me if they aren't equivalent terms) motion towards the quarterback but then moves back to his original position?

To me as a outsider, it seemed pointless that he moved to near the center position and then back to his original spot.

Wikipedia does discuss the purpose motioning but it speaks about changing formations. If the receiver moves to his original position the formation is the same.

Also, I could see motioning to the other side would make sense to provide extra protection for a screen to a running back play.

During the presnap is there a purpose for motioning the slot receiver toward the center and back to his original position? Is it to test the defensive positions?

Answer 1

The answer you accepted is undeniably incorrect for the NFL - I know it is an old question and answer but this needs a correct answer. Yes NFL teams may have their slot motion to drag a man defender over to a particular side of the field. Just because he moves with the receiver is not even a "good" indication that they are playing man. A lot of teams employee man-zone principles where they will employ man coverage underneath or on set players and zone elsewhere. The safety and corner splits are a better indicator and using this to guess is why bad QBs throw a lot of stupid picks.

Acting like an NFL team is playing man coverage because the defender moves with him is exactly what they want you to think. After the QB sees the slot receiver beat the man press and then the DB settle down into the shallow zone he releases the ball, not understanding that a safety has over the top responsibilities... too late. Just because this works in old versions of Madden doesn't make it true.

Reasons for putting a slot in motion:

• the most common reason is to get a smaller WR out of press coverage. If playing against a team with hard press concepts and a good press corner your slot guy could spend most of the day playing handsies without ever running a route. Going in motion makes it harder to press him and really impossible with a smart QB.

• a well coached team will use a motion man to create a mismatch on defense. So if you have a slot WR with a very fast #2 WR you can throw your slot in motion to see if the corner will follow. If corner follows you have a speed matchup.

• to set picks. This is en vogue right now in the NFL but basically the slot guy motions to twins and does a flat rub. As he does his flat route the twins both wait and release inside of him which causes some really odd angles for the DBs. (a friend noted that the slot guy also motions over and fakes the rub and outside receiver runs a streak fade as DB deeks for inside position)

• if the QB is having a hard time reading the coverage the slot guy will often motion to produce a trips or quad situation. By having a bunch of trips or quads on a side you are forcing a team to shell into some sort of man concept most of the time.

• just to cause general confusion. Basically by putting a man in motion - let's say hard motion from one side to another - you are basically making up to 7 guys on the defense all be on the same page on a possible total coverage change. A motion man swapping could change the call from zone to man or vice versa. If one of those 7 guys makes a mental mistake then you may have a free WR running downfield.

Yes you could put a slot in motion to guess man defense but this would be akin to reading the knuckles of offensive lineman to guess run or pass.

Answer 2

One of the purposes of motioning a receiver is for the quarterback to discover whether the defense is playing man-to-man or zone. If a defender follows the receiver, the defense is likely playing man-to-man; if the defense remains (relatively) stationary, they are likely playing zone (defending areas of the field instead of specific players).

The quarterback can use that information to determine which receivers are most likely to be open or whether he should hand the ball off instead.