Why are combined no hitters so rare?

Question

The other day, the Astros pitched only the 14th combined no hitter in MLB history by a starter and reliever(s). I believe that there were actually more than 14 complete game no hitters by only starters.

Why would there be fewer combined no hitters than complete game no hitters? I would imagine that it would be easier for "fresh" pitchers to avoid getting hit than someone who had to pitch all nine innings. Or is this somehow not the case?

Answer 1

The simple answer is that there are very few chances for such a feat. Pitchers are usually replaced when they're being ineffective, not when they're doing a good job.

I'd say you'd generally need have to have one of:

• Using an "opener"
• Injury to starting pitcher
• Hard pitch count limit

to create such an opportunity. Otherwise the manager is going to tend to leave the pitcher place to reward the execution and see if the starter can get the no-hitter alone.

The Angels combined no-hitter earlier in 2019: Taylor Cole started the game as an "opener" and would not be prepared to pitch a complete game.

The Astros combined no-hitter against the Yankees in 2003: started by Roy Oswalt, who had an injury in the first inning and had to leave the game.

At 6 innings and 92 pitches, Aaron Sanchez was pulled on a pitch count limitation. That's pretty low for a starter, but I couldn't immediately find the reason for the limit.

Use of an "opener" has been experimented with quite a bit recently and teams are more protective of pitchers with pitch counts. So you could reasonably expect the rate of combined no-hitters to go up over time.

Answer 2

Baseball has a lot of "unwritten rules". One of these is that a pitcher who is in the midst of a possible no hitter is kept in the game until he completes the no hitter or gives up a hit. This is probably because throwing a no hitter of any sort is a rare feat, and a starting pitcher who is taken out of such a game may be upset if he is taken out and denied the opportunity to complete the game.

That said, there are obviously situations where a pitcher who has not yet given up a hit is replaced.

• As noted in BowlOfRed's answer, some teams are experimenting with an "opener" - a pitcher who only pitches a few innings at most. Such a pitcher is unlikely to be "stretched out" enough (i.e. he probably has not built up the endurance) to pitch a complete game.
• Related to the above point: Statistical analysis has shown that batters become more effective when they see a pitcher multiple times in one game. Thus theories of using pitchers seem to be advancing in the direction of limiting pitchers to only one time through the batting order - a theory I first heard from Chuck Tanner (then manager of the Pittsburgh Pirates) back in the late 1970's or early 1980's.^*
• Teams often have pitch count limits for their pitchers that they won't surpass (by much). This is often to reduce the chance of injury. For example, a pitcher with a limit of 100 pitches will be pulled out of the game around that limit (they will often be allowed to finish a batter or inning) even if they have not yet allowed a hit - especially if he's not yet into the ninth inning.
• Injury or ejection may lead to the replacement of a starting pitcher who has not yet allowed a hit. One somewhat famous case is when Babe Ruth was ejected after walking the first batter and arguing with the umpire. Ernie Shore relieved Ruth, picked off the base runner, then didn't allow another base runner for the remainder of the game.

^*IIRC, Tanner actually said he would like to replace the pitcher every three innings, which would be the equivalent of once through the batting order (i.e. each batter appearing at the plate once) if no one reaches base in that time.