Tuesday, February 16, 2010

Josh Beckett's fluky home-run rate

It's easy to forget now that Josh Beckett looked like a Cy Young candidate as late as mid-August last season. The hard-throwing righty had a 3.10 ERA and a strikeout-to-walk ratio of 3.45. His win-loss record was 14-4, for those who care about that sort of thing. He'd thrown three complete games, including a three-hit shutout against Kansas City and a three-hit shutout against Atlanta.

Heck, he'd even hit a home run.

But the longball started to cause problems for him in late August, and his ERA reacted accordingly. By Sept. 2, Beckett had allowed at least two home runs in five straight starts and had seen his ERA jump to 3.87 -- and Jon Lester was the Game 1 started in the ALCS.

Home runs are one of those complicated things pitchers both can and can't control. A pitcher has a degree of control over how hard the ball gets hit, and how hard the ball gets hit has a lot to do with whether it goes over the fence. There's a little bit of luck involved, though, in whether fly balls turn into home runs or whether they end up caught at the warning track.

A look at Beckett's entire season indicates that he probably got a little bit unlucky during his rough patch in August.

(Thanks to FanGraphs' tremendous new splits tool for the data.)

Beckett saw his ground-ball rate stay pretty consistent last season, spiking at 52.2 percent in June but never falling below 46 percent down the stretch. His fly-ball rate wasn't quite so consistent, jumping from 28.3 percent in June to 38.9 percent in August. At the same time, though, his line-drive rate hit a season low in August -- and line-drive rate usually is a better indicator of pitcher success or failure than either of the other two measures.

Even as his fly-ball rate jumped, his home-run rate jumped even higher -- higher than it had in his entire Red Sox career. Check out his HR/FB rates by month last season:

Home runs out of total fly balls
10.0 percent
May: 13.0
June: 3.8
July: 8.1
August: 27.3
September: 8.6

(Cue the outlier music.)

Not once in his Red Sox career has Beckett had a month even close to that bad. Not once in his Red Sox career has Beckett's HR/FB ratio even touched 20. His previous worst came in 2006 when his HR/FB numbers fluctuated between 11.1 and 19.5 percent. More often than not, his HR/FB ratio has been under 10 percent.

In other words, something looks awfully fluky about the rough August that Beckett endured last season -- and that's an encouraging sign for this season.

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