Starting Pitcher Ground Ball Rate Surgers

Batted ball distribution rates stabilizes more quickly than most of the other offensive and pitching statistics. We have found that ground ball percentage becomes reliable at about 200 plate appearances. Though no pitcher has quite reached that level yet, we are fairly close. It is therefore worth checking in on those pitchers whose ground ball rates have surged since last season and see if we can figure out if any are sustainable. All else equal, a high ground ball rate should result in fewer home runs, and ultimately a lower ERA.

I originally discussed Jason Hammel at the end of March as a potential strikeout rate surger based on his spring training numbers. Well, not only has that happened so far, but he decided to improve another facet of his game as well, his ground ball rate. It had always been a tick about league average, but he now ranks fourth in the Majors in GB%. According to the PITCHf/x data, he has increased his two-seam fastball usage from 13.1% to 40.5%, while his four-seamer is now only being thrown 20.9%. That alone is about enough to explain the huge jump. In fact, he has induced a 73% ground ball rate on that two-seamer against righties. Though it is difficult to bank on the magnitude of this increase lasting, he does seem likely to post a 50%-55% ground ball rate the rest of the way.

In his earlier days, Cliff Lee was a fly ball pitcher. Then, when he transformed suddenly into one of the best pitchers in the game in 2008, he also increased his ground ball rate to around the league average overnight. It has been in the low-to-mid 40% range ever since, until this year. He is throwing his cutter and change a bit more than last season, primarily at the expense of his four-seamer, but the change in pitch mix doesn’t seem drastic enough to explain the GB% surge. I would bet his ground ball rate falls and I would be surprised if it ends above 50% by the end of the season.

This would be huge for Brandon Beachy because the only knock on his skill set is that he had been a fly ball pitcher. Right now, he is inducing a ton of ground balls against left-handers, including a nearly 64% mark from his four-seamer. He posted just a 32% rate against them last year with the pitch. He has thrown his four-seamer a little less often in favor of some other pitches that do induce slightly more ground balls, but like Lee, this seems rather flukey. Expect some regression here as well.

Can you imagine if Clayton Kershaw was an extreme ground ball pitcher, while still maintaining his strikeout and walk rates? We can see just how trading off some strikeouts for ground ball affects a pitchers’ SIERA, as Kershaw’s BB% is identical to last year, while his K% has fallen and GB% has risen. His SIERA though, is nearly the same, at just 0.07 higher. Of all the pitchers discussed so far, his pitch mix has been altered the least since last year. So I have to think this is a complete fluke and he is going to drop back down to the low 40% range where he has typically sat.

Being a fly ball pitcher as a San Diego Padre is not such a bad thing, but Cory Luebke is ensuring he could pitch successfully on the road too with an increased GB%. His pitch mix has indeed changed and looks more like Hammel then the other three so far. He has suddenly started throwing a two-seamer nearly 21% of the time, after throwing it just about 3% last year. Given that part of his low GB% was the result of a higher than league average LD% last year, this increased GB% looks relatively sustainable since some of those line drives were also going to become grounders.

Wow, if there was ever a pitcher who needed something to help cure his poor luck, it is Ricky Nolasco. His pitch mix differs depending on whether you look at the FanGraphs or PITCHf/x classification. One tells us he has increased the usage of a splitter, which should induce more grounders, while the other say he has thrown his change-up more often. Either way, whatever the pitch is labeled, it is coming at the expense of his four-seamer, which is a good trade-off as far as getting ground balls. The altered approach though doesn’t seem to be enough to explain such an increase in ground ball rate, so expect it to regress a bit. However, assuming he continues with the change, he could set a career best GB%, but it will likely be closer to 50% than 60%.

Edwin Jackson has posted a nearly 50% ground ball rate before, so this isn’t as surprising as some of the others. However, even though a 7.5% line drive rate is an amazing feat so far, it is obviously not sustainable. Once that line drive rate jumps back to the high teens, the ground ball rate is going to fall. His fly ball rate is right at his career average already, so this is pretty much a lock. Oh, and his four-seam usage has actually gone up 20%, while his two-seamer usage has declined 16%.

I am beginning to think that Jeremy Hellickson is some sort of robot placed on this Earth simply to boggle the minds of sabermetricians. If you thought he was lucky last year, now he’s just laughing at us. Most of the GB% increase falls under the same reasoning as E-Jax above, as Hellickson’s LD% sits at just 13.9%, while his FB% is only 4.5% below last year.

For the first time, Joe Saunders has a SIERA below 4.00! He can thank all those additional grounders he has induced so far. He had been amazingly consistent with his GB% in past years, posting marks between 42% and 48% every single season. Some of this jump does appear to be legit, as he has increased his two-seamer usage from 30.5% to 47.6%, mostly at the expense of his four-seamer. Even with the GB% jump, only another huge heaping of luck will allow him to generate any mixed league value.

An increased ground ball rate would be a huge help for James Shields who has suffered from a higher than league average HR/FB ratio nearly every season. I think some of this is for real as he has increased his cutter usage (PITCHf/x says slider, but from watching him pitch, I am pretty sure it’s a cutter) from 15% to 26%, while cutting his fastball percentage for the second straight season. His fastball is easily his worst pitch so from an overall effectiveness stand point, this is probably a good move. Like some of the others, it is hard to believe Shields’ ground ball rate will remain this high, but a career high near 50% may be attainable with his pitch mix change.