There is a radical difference between starting a game and making an appearance out of the bullpen.
This disparity is due to multiple factors. Starting pitchers are out on the mound once every five days while a relief pitcher can be called upon at any time. Relievers must be able to shake off a bad outing and be ready for tomorrow’s game; having a short memory is fundamental to a reliever’s success. A starter has to have longevity while a reliever could face one batter before his job is done.
Starters and relievers have two different states of mind, and some pitchers struggle when forced to switch responsibilities. Take Milwaukee Brewers reliever Tom Gorzelanny, for example. Gorzelanny spent his first five seasons in the majors as a starter, but after mediocre work, he was shifted to the bullpen full-time in 2011. Credit the Washington Nationals for this brilliant move.
For his career, Gorzelanny has a 4.62 ERA as a starting pitcher. Pitching out of the bullpen, however, he boasts a 3.17 ERA, an indication that he was able to succeed with the different mindset that is relief pitching. The Brewers signed the left-hander to shore up their need for a southpaw in the bullpen but, because of injuries to the starting rotation, he made a 10 spot starts in 2013, assembling an earned run average of 4.81 in those starts while maintaining 2.70 ERA as a reliever.
All across the board, Gorzelanny’s career numbers are better when pitching in relief. His K/9 is higher while his HR/9 is lower and he holds opponents to a .210 batting average versus a .266 average as a starter. Hitters no longer have the opportunity to see Gorzelanny more than once in a game and since he does a nice job of hiding the ball during his delivery, he has the upper-hand.
Gorzelanny didn’t pan out as a starter but luckily for him, he’s been able to get the job done in the bullpen, extending his playing career.