Quote:
Originally Posted by Righty Groove
You may be familiar with Tom Tango's work, right? Well, I won't cite him specificlly but, of the top of my head, he has a rule-of-thumb that, when a pitcher transitions to the bullpen, his K% improves 17% and his BB% decreases 17%, with the opposite happening when the transition is bullpen to rotation.
The reasons are difficult to prove or disprove, more anedoctal then anything. But, basically, relief pitchers throw more fastballs (higher in-zone%), hitters are less inclined to drive up his pitch count (as they would with a starter, perhaps), and when you focus on your best one or two pitches it's easier to throw strikes.
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Actually, what Tom Tango said was that K-rate when up 17%, but the walk rate remained the same. Pitchers don't dramatically increase their control because they're throwing "lights out."
From Tom's blog: "You can try slicing and dicing Rally’s data any way you like, but you will see little bias in eras. Basically, use the “rule of 17”: difference in BABIP is 17 points higher as starter. K/PA is 17% higher as reliever. And HR per contacted PA is 17% higher as starter. Walk rate is FLAT."
http://www.insidethebook.com/ee/inde...ief_1953_2008/
Also - doesn't Markus already compensate for this? I thought I heard him mention that pitchers get a bonus when they are relieving as opposed to starting.