My new favorite toy is Baseball Prospectus’s WXRL, a more reasonable way to measure relief pitchers’ performances. The final product of WXRL, which stands for “Win Expectation above Replacement, Lineup-adjusted,” is a straightforward number that looks like ERA — except the higher, the better.
As I’ve mentioned before, Brad Hennessey leads the Giants this year. His current 2.62 score means he’s contributed about two and a half more wins than a replacement-level player. He added nearly a full win to his score thanks to a strong August, moving from #48 in the MLB to #38. (The major-league leader is Seattle’s J.J. Putz at 6.05.)
Unless Hennessey makes a similar push in September, it will be only the third time since Robb Nen took over in 1998 that the team’s top reliever has contributed fewer than three wins. The others: Kevin Correia in 2006 (1.83) and Jim Brower in 2004 (2.55).
A low-scoring top thrower isn’t necessarily bad: in 2003 Tim Worrell led S.F. with a 3.90 WXRL and placed 15th in the majors, but the team had four others in the top 60.
To give you a sense of what it takes to accumulate one WXRL “win,” note that Brian Wilson has thrown 10 2/3 scoreless innings in his 10 appearances and has a WXRL score of 1.20.
Here are the highest season totals of the past ten years:
Eric Gagne 2003: 9.24
Trevor Hoffman 1998: 8.28
Keith Foulke 2000: 8.21
Gagne 2002: 8.20
Brad Lidge 2004: 8.10
Ready for a quiz?
Since 1990, which Giant reliever has posted the highest single-season WXRL? Name the player, the year, and the position he finished among all major-leaguers.
If you subscribe to Baseball Prospectus, no peeking.
