2018 Starting Pitcher GB% Decliners

Yesterday, I discussed the starting pitchers who have experienced the largest spikes in ground ball rate. In the era of the fly ball and home run, it’s more important than ever to induce the batted ball type that cannot leave the park — the grounder. Today, let’s dive into the starting pitchers who have seen their GB% dive compared to last year. Remember we’re still dealing with tiny samples here, so it’s likely the majority of pitchers regress toward their career average. But that won’t always be the case, so it’s worth trying to catch the batted ball type distribution changers early.

Meet Gerrit Cole, version 2.0. In his first year in the American League with the Astros, he has nearly eliminated his sinker usage and dramatically upped his slider usage. Obviously fewer sinkers should lead to fewer grounders, and Cole’s career GB% on his sinker is 55%. But his slider was just above 50% too. The difference, then, is that his slider’s GB% is down to just about 29% and he literally hasn’t induced a grounder on his curve (30 of them) yet. Is he throwing his pitches higher in the zone? Nope, every pitcher is actually lower in the zone versus last year. Most of the decline in GB% could be traced to his absurd 36% LD%. It’s a wonder he’s managed to hold a .240 BABIP allowing so many line drives!

Brent Suter has also suffered from an insane line drive rate, and his FB% is where it’s been in the past. It appears his mark last year was a bit of a fluke. I would want no part of him.

When he first debut, James Paxton’s big appeal for me was his high ground ball rate and strikeout ability. The strikeouts finally came last year, but his GB% has tumbled since his debut in 2013. Suddenly, he’s an extreme fly ball pitcher. His velocity is fine and pitch mix hasn’t changed much, so this is odd. I’m curious how he fares in the near-term and whether this new profile sticks. He’s far less exciting as a fly-baller.

Add Zach Davies into the high LD% group. At least he has offset all those flies with a surge in SwStk% and strikeout rate. He’s one of the few whose velocity is actually up, but his pitch mix is essentially the same so again it’s difficult to explain the change in batted ball distribution. He might be playable in NL-Only if he could maintain an improved SwStk%.

For all the talk of Chris Stratton’s curve ball spin rate, the strikeouts haven’t followed. He’s another member of the inflated LD% club and he’s allowed more liners than any other batted ball type! Until that curve ball translates into strikeout ability and better results, he’s nothing more than an NL-Only gamble.

Zack Greinke should be fine, as once again he’s suffered from a high LD%. Those liners should turn into grounders and his distribution will be back to normal. More concerning, however, is fastball velocity averaging below 90 mph for the first time in his career. Naturally, he boasts a 14/0 K/BB ratio in 10 innings so far, so clearly that velocity loss hasn’t hurt!

Finally, Ian Kennedy marks the last of the pitchers on this list who are here thanks to a high LD%. His strong outward results so far are surely getting him picked up in most leagues. But his SwStk% is right at his career average and he’s not going to walk just 4.4% of batters. Basically, he’s the same guy he has been. It’s still a guy I kinda like given his home park and defense, but don’t get too excited.

Robbie Ray was a fly ball pitcher last year, but he has taken that to the extreme this year. Perhaps he has done this consciously given the presence of the humidor, thinking fly balls will go to die now when previously they had flown out of the park. It hasn’t actually worked though, as he’s already allowed three homers in just five innings of work at home.

Sheesh, without the mid-50% ground ball rate, Jaime Garcia becomes far less interesting in AL-Only leagues. His pitch mix is similar, but velocity is down, and when you get below 90 mph, bad things could happen.

Trevor Bauer posted FB% marks around 40% during his first two full seasons, then transitioned to more of a ground ball guy the next two. Now, he’s back to his 40% ways. So far, he’s made a big pitch mix change, essentially eliminating his cutter and sinker in favor of more sliders. What’s interesting is he was at this slider level in 2015, the last time his FB% sat at 40%. However, the GB% on his slider isn’t much different than the majority of his other pitches, so mix alone doesn’t explain this change. Instead, he’s getting a ridiculously low 6.3% grounders on his fastball and his curve GB% is less than half his career average. A consolidated repertoire is what we’ve been waiting for and all he needs is some better HR/FB rate luck to finally get his ERA below 4.00 for the first time. I’m optimistic.

You guys explained to me that Luis Castilo’s GB% spike was due to him throwing his sinker more often. I argued that the small increase in usage alone couldn’t possibly explain such a surge. Obviously, it’s wayyyyyyy too early to toot my own horn about being right, but Castillo’s GB% mark is right back between his 2016 and 2017 marks while in the minors. He’s even throwing his sinker 17% of the time now, up from about 11% last year. Although the sinker has continued to generate tons of grounders (though not as high a rate as in 2017), it’s mostly been the changeup that has killed his grounder rate. That’s fine though as it’s generated an insane 42% SwStk%! That’s not a typo. What’s also not a typo is that somehow Castillo owns a 16.2% SwStk%, but just a 19.6% strikeout rate. If you can get him at any sort of discount, I’m buying all day.