Abandoning The Four-Seam Fastball: A Case Study.

If Corey Kluber‘s road to the big leagues was long and winding, the reason for his recent success might be short and simple.  Some time in 2011, he gave up on his four-seam fastball and started throwing a two-seamer. After learning more about Kluber from a Spring Training interview he gave with SportsTime Ohio, I thought about the impact that one little move had on the pitchers career.

It was a tipping point.

Kluber has always had outstanding off-speed stuff: His change-up (22%), slider (20%), and cutter (15%) are all above-average by whiff rates. The list of other starting pitchers with three above-average whiff rates on offspeed pitches is very short: Yu Darvish, Matt Harvey, Felix Hernandez, Tim Lincecum, and Jerome Williams. That last name, the last two names these days, both should give you pause for concern. “All of that other stuff plays off the fastball, if you’re not consistent with the fastball, none of that other stuff is going to be as good,” said Kluber before a game against the Athletics this week. However, after a lackluster first start in Oakland, we are left to wonder if Kluber is following down that path.

Despite having a great mix of secondary pitches, Kluber has had to find his way to the big leagues by improving his fastball. “I was getting hit around and was having trouble working consistently down in the zone,” said Kluber of 2011, when he had an ERA over five in Triple-A. Pitching coach Mickey Calloway and then-Triple-A pitching coach Ruben Niebla conferenced with the pitcher and advocated the two-seamer. The change has taken to Kluber — “I hardly ever throw the four-seamer any more.”

Kluber is getting used to the pitch: “It’s a pretty drastic change to throw the ball differently than you’ve thrown it your whole life,” he said, adding that he’s getting more comfortable with it every day despite the change-up being his biggest “feel pitch” that requires as much practice. A little uptick in velocity on the fastball and improved walk rates seem to reflect that he’s good with the two-seamer now.

This transformation, at least in retrospect, seems so easy. Three main fastball grips are there for pitchers to use, and they’ve been fiddling with that pitch the longest in their lives. The fastball is the first thing you’re allowed to throw.

What I wanted to find out was: Is there a predictable pattern with pitchers who throw nothing but four-seamers  who would be good candidates to start throwing two-seamers instead.

I suppose we’d be looking for a four-seamer with a bad K/9 rate on a pitcher that doesn’t already throw many two-seamers. Taking only those starters that threw more than 750 four-seamers last year, and then sorting those for the worst whiff rates, you get 20 pitchers who get fewer than 4.5% swinging strikes on their four-seamer (the average four-seamer in that group got a 6.7% swinging strike rate). Here are those 20, with their number of two-seamers listed in the last column.

All numbers come from Brooks Baseball:

Among the younger names, though, it’s hard to spot someone with the offspeed resume that Kluber had when he made the change to his fastball grip. Scott Diamon has actually been throwing more two-seamers lately by Brooks Baseball (the numbers above are from our PITCHF/x database) and they are getting 63% ground balls. Though he only has the plus curve otherwise, it could make him more valuable than he was in the past. Considering how good Tyson Ross‘ slider is, and the fact that his 200 or so two-seamers got a 73% ground-ball rate, and that his four-seam didn’t get the whiffs you’d like, maybe more sinkers would serve him well (despite the platoon splits).

Justin Grimm has a good curve, slider and a change-up he can use for grounders. His four-seam didn’t get whiffs or grounders last year, and his two-seam got 63% grounders. By Brooks Baseball, Paul Clemens didn’t throw a two-seamer despite a bad four-seamer and a good change and curve — with his poor ground-ball rate, he might be a prime candidate to start throwing a two-seamer. Tom Koehler gets good strikeouts on a change and slider combo, but his four-seam ended up on this list.

There is no real predictable pattern in which I could detect. However, it might benefit the pitchers on this list who are similar to Kluber to start throwing the two-seamer.

Kluber should continue to use his two-seamer like he did last season. He threw way too many offspeed pitches in Oakland.