Randy Wolf and evolution

Season	Age	WAR	tRA
2002	26	3.5	4.30
2003	27	2.4	5.18
2004	28	1.6	5.71
2005	29	0.5	6.18
2006	30	-0.3	6.97
2007	31	1.7	4.23
2008	32	2.0	4.76
2009	33	3.0	4.27

What happened here that created this inverted bell-curve (if our x-axis was time and our y-axis was WAR)? Keep in mind 2002 was Wolf’s fourth year in baseball. Here are his earlier FIPs:

1999: 5.14
2000: 4.48
2001: 3.50

So, Wolf came up to the big leagues and got off to an okay start in his first two years. In his next two years, he then established himself as a legitimate front-of-the-rotation starting pitcher. But then in 2003, when he should be reaching somewhat of a peak, he begins to regress pretty rapidly. By the age of 29 he’s barely holding on to a major league job.

It looks as if Wolf got off to a hot start, and hitters simply began to catch up to him, which happens with all pitchers. But the tipping point was in July of 2005, when Wolf had Tommy John Surgery. His comeback in 2006 marked the bottom of that inverted bell curve, as he had by far his worst season in the majors. Coupled with Wolf’s comeback from injury was the opening of Citizens Bank Park in 2004. Wolf’s HR/FB% from 2004-06 were 10.5%, 13.6%, and 16.7%.

He’s now a different pitcher. His injury/surgery/time off wouldn’t allowed him to be the same pitcher he was pre-2005. In his early days, he had a higher velocity fastball and threw it by hitters. Now, he uses plus secondary stuff to get hitters off-balance. In 2003 and 2004, he used his slider just 3.1% of the time. He threw it 13.2% last year, 13.9% this year. His K/9 this year is the second-lowest of his career, but so is his BB/9. Billy Beane recently told us, “The one thing about major league baseball is that it’s pretty Darwinian.” Just like Darwin realized that the birds of the Galapagos were two different species of Finches (and not different birds altogether), Randy Wolf hasn’t become a “different” pitcher. He’s still Randy Wolf. He’s just adapted.