An SU pitcher in baseball is a setup pitcher, or setup man, who typically works the innings right before the closer comes in to finish off a game.

In order to understand the role of the setup pitcher, it’s helpful to get a handle on the different types of pitchers a baseball team might use during the course of a game. These include:

  • Starting pitcher – the pitcher who pitches from the beginning of the game; traditionally, the goal has been for a starting pitcher to throw all 9 innings, but changes in pitcher use patterns during the 21st century have made 6-7 a more common hallmark for starter durability.
  • Long reliever – this pitcher comes in to relieve when the starter leaves early in the game; a long reliever will often pitch two or more innings, and a manager may need to call on multiple long relievers in one contest if the score gets out of hand or if the starter leaves after just an inning or two.
  • Mop-up reliever – this pitcher comes in late in a game to finish up when the score is lopsided in either direction; the traditional connotation, though, has been that this pitcher comes in to clean up, or “mop” up, after his team has made a mess of the game.
  • Closer – this is the lockdown ace of the relief corps, the pitcher most often charged with protecting a small lead in the late innings; in the 21st century, most closers only work the ninth inning of one- or two-run games, but some are used for longer stretches or in other situations.
  • Setup reliever – the setup man is usually another sure thing in the manager’s mind, and it’s his job to bridge the gap between a starter or long reliever and the closer; often, a setup man will work just eighth inning, though some will work a couple of innings leading up to the closer.

So, as you can see from those descriptions, a setup reliever literally sets up the end of the game for the closer to come in and work his magic.

Setup men don’t always get the glory that closers do, but they are just as indispensable to their teams. And many a great setup man has “graduated” to the closer role when the incumbent moves on or melts down.

Did you know? Hall of Fame reliever Mariano Rivera was one of the greatest setup men of all-time before he became the New York Yankees’ closer. Sort of like the all-mound version of Babe Ruth!