Many people, including yours truly, have written about the excellent bullpen of the Kansas City Royals, and very few have written about the considerably less excellent bullpen of the San Francisco Giants. The Royals led all of baseball in reliever fWAR; the Giants were 28th. (Side note about the above linked chart: WOW was the Mets' bullpen awful.) The Royals had two relievers in the top eight in FIP and three in the top 25; the Giants' top qualifier was Jeremy Affeldt at 37th. (Yusmeiro Petit didn't have enough innings.) Throw in the turmoil at the back end with Sergio Romo being replaced at closer early in the season by Santiago Casilla, and relief pitching seemed to be a clear advantage for the Royals.
That narrative, like so many others, has been turned on its head by the Even Year *Magic* of the Giants. Having Madison Bumgarner go deep into games certainly doesn't hurt, but San Fran's bullpen has allowed only three earned runs in 14.2 innings (1.84 ERA), while the vaunted Royals relievers have given up twelve in 19.2 innings (5.49). They have been asked to do a lot, with no Royals starter going more than James Shields' six innings last night and Shields (in Game 1) and Jason Vargas not even getting to the fifth. We're not here to talk about KC's struggles, though, but rather SF's excellence.
First, let's get the bad out of the way: Jean Machi and Hunter Strickland were objectively terrible by any measure in Game 2, giving up three runs between them without recording an out. Even with those performances included, the Giant relievers' RE24 during the series is 2.0, far outpacing the Royals' -5.0. Take Machi and Strickland out of the mix, and the Giants' mark shoots all the way up to 6.4. They've been led by Javier Lopez and the aforementioned Petit, who have thrown 3.2 scoreless innings in total. Tim Lincecum (remember him?) also put in 1.2 perfect innings before straining his back in Game 2 but is apparently fully healthy and ready to go for Game 6 and a possible Game 7.
Petit has been the big story this postseason, dominating in Game 4 and keeping the Giants in the game until Brandon Finnegan and the Royals imploded. (For good measure, he managed just the sixth hit of his career as well, the first in the World Series by a reliever since 1993.) He's struck out 13 batters in 12 innings while allowing only four hits. Below is his batting average against profile for the postseason.
Pretty darn good, eh? All in all that's four hits on 38 at-bats, a .105 average. What's the secret to his newfound success, though? Before 2013, Petit had never posted a FIP under 5.21 in 2008. A quick look at pitch usage reveals a trend:
Petit reallocated a significant portion of his fastballs to his curve, and it's made quite the difference. Opponents have hit only .154 and .170 on the curve the last two years, down from well over .200 previously. It was working during his impressive streak of retiring 46 straight batters, an MLB record. Examine the pitch that got him the 46th, on a strikeout:
That's some serious movement – his curveball falls about ten inches below his fastball on average. With Petit complementing the established Affeldt and Casilla (and Romo in the mix as well), the Giants may have found themselves a big three to match the Royals' for years to come.
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Steven Silverman is a featured writer at Beyond the Box Score and a student at Carnegie Mellon University. He also writes for Batting Leadoff. You can follow him on Twitter at @Silver_Stats or email him at Steven@SilverStats.com.