Fluke Watch: Tim Stauffer

San Diego Padres pitcher Tim Stauffer came up in 2005 at the age of 23 and threw 81 pretty poor innings, basically at replacement level. Sent back to the minors, Stauffer wouldn’t get another chance to contribute until four years later, when he threw 70 or so replacement-level innings.

Stauffer didn’t strike many batters out, walked too many batters, and didn’t get many ground balls. There was nothing about him in 2009 that made anyone think he’d be anything more than a reliever or a fifth starter, at best.

Two years later, Stauffer’s numbers have totally changed. The strikeouts remain the same, but his walks have fallen in half and suddenly he’s a strong GB pitcher. Where did this come from, and is it for real? He’s kept it up for two half-seasons now, but can he be trusted? Short answer: Yes.

Stauffer’s pitches

Tim Stauffer’s thrown five pitches since 2008: A four-seam fastball, a two-seam/sinking fastball, a change-up, a slider/cutter (it’s a pitch that’s in between, and I don’t know what he calls it) and a curveball. The two major pitches he’s thrown are his fastballs (a combined 47-53 percent of the time against lefties and righties, respectively) and his slider, which is used 25-30 percent of the time against both types of batters.

Now, Stauffer’s fastballs are not easy to tell apart in Pitch-f/x data. However, they are clearly different pitches, with the two-seamer having more sink and tail than the four-seam pitch. And it’s very clear: In 2009, his main fastball was his four-seam fastball. But in 2010-2011, Stauffer switched fastballs and now almost exclusively uses a two-seam fastball.

This fastball change has had a large impact on Stauffer’s results and is almost certainly the cause for his improvement over the last two years. His fastballs in 2009, comprising mainly of four-seamers, were only average at getting whiffs, while being a clear flyball pitch (with a GB rate under 40 percent against both lefties and righties).

In 2010-2011 however, Stauffer’s fastball has been a groundball machine, getting ground balls around 60 percent of the time against right-handed batters and just under 50 percent against left-handed batters (this type of GB split is normal for two-seam fastballs.)

Stauffer also has managed to hit the strike zone more often with his fastball since the switch, which explains his reduced walk rate. It’s not a huge increase in zone accuracy, but it’s enough to force batters to have to deal with his pitches with their bats as batters are no longer quite able to let the pitches go past for ball four.


Indeed, Stauffer looks like the real deal. One caveat is that I’m not sure his improvement in walk rate this year from last year is real. There doesn’t seem to be an increase in accuracy (if anything, there’s a tiny decrease) that would explain the walk rate decrease, and the difference is certainly small enough simply to be explained by randomness.

So if I had to make a prediction for him going forward, it would be for him to produce results equal to his average performance over the last two years.

But the walk decrease from 2009 is real. As is his emergence as a serious groundball machine. Stauffer may not be bringing you a ton of Ks—his swinging strike rate has actually dropped from his old 2009 days due to the two-seamer being a worse pitch for getting swings and misses.

But he’ll give you a pretty good ERA and as many wins as you’ll probably be able to get from a weak-hitting team like the Padres, and unlike some other pitchers San Diego has had, since his success is not dependent upon the home run-suppressing features of PETCO park, as his ground balls will play well in any park.

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