Charlie Morton’s Crazy Platoon Splits

After Charlie Morton’s first three starts of the season, his ERA stood at 1.64, and I noted that his revamped style of pitching simply wouldn’t let him keep this up for much longer. Since I wrote that article, Morton has made five more starts and posted an ERA of 3.27 – technically that does represent regression, but it’s still better than I would have expected. After another dominant start last night, I figured we needed to take another look at the guy they call Ground Chuck.

In Morton’s last five starts, he has reduced his reliance on his sinker, going from 90% fastballs in his first three starts to “just” 80% in his last five. He’s still basically just throwing one pitch, but he has mixed in his off-speed stuff a bit more in order to be a little less predictable. It has helped as well, as after posting a 12/6 BB/K ratio in his first three starts, he’s at 14/23 in his last five. The decrease in fastball usage has led to fewer walks and fewer ground balls, but overall it’s been a worthwhile trade-off for Morton – his xFIP has dropped from 4.09 in April to 3.63 in May- putting fewer men on base outweighs the small change in his batted ball profile.

But there’s still an area that has to be cause for concern with Morton, and it’s directly related to the changes he’s made to his repertoire. Morton has decided to lean on a two-seam fastball more heavily than just about anyone in baseball, and as Dave Allen has noted, the two-seam fastball and the slider have the largest platoon splits of any pitches in baseball. Two-seamers are great against same-handed batters, but aren’t an effective weapon against opposite-handed hitters.

Morton’s splits show that he’s no exception to the rule. After posting fairly neutral splits last year, Morton has one of the largest gaps of any pitcher in baseball this year.

Vs RHBs: .156/.224/.178, 2.56 FIP, 3.14 xFIP
Vs LHBs: .385/.488/.538, 6.75 FIP, 5.82 xFIP

He’s turning opposing right-handed batters into something like a mediocre hitting pitcher while left-handed batters are teeing off on him at a rate that would put them on the All-Star team. His BB/K against righties is a solid 12/25, but against lefties, it’s 14/4. Since Morton is attacking lefties almost exclusively with a pitch that doesn’t work against them, he’s essentially unable to get them out.

So, how does a guy with that kind of vulnerability to left-handed bats have a 2.64 ERA through eight starts? Put simply, he’s gotten pretty fortunate in the kinds of lineups he’s faced so far.

148 of the 228 batters that Morton has faced this year – a whopping 65% – have been right-handed. The average for all right-handed pitchers in the majors this year is 52%, and that includes relief pitchers who can be selectively used to exploit platoon match-ups. Most starting pitchers have to face predominantly opposite-handed line-ups, and managers especially tend to stack the deck with left-handed bats against RHPs who have demonstrated massive splits.

Yet Morton’s opponents so far have run mostly right-handed line-ups at him because they happen to have more right-handed bats than average. For instance, here’s the line-up the Reds threw at him last night.

Stubbs (R)
Janish (R)
Votto (L)
Phillips (R)
Rolen (R)
Lewis (L)
Gomes (R)
Hanigan (R)
Arroyo (R)

That’s a line-up made to be shut down by a guy like Morton. You pitch around Votto and attack everyone else, and that’s exactly what Morton did. It’s probably worth noting that both of his complete games this year have come against the Reds, who have only managed one run against him in those two matchups.

Morton’s worst start of the year came against the Marlins back on April 20th as he gave up six runs in five innings. Florida started Chris Coghlan, Greg Dobbs, and Emilio Bonifacio against him. Not exactly a murderer’s row of left-handed thumpers, but those three managed five of the 10 hits off of Morton. His other poor start of the season came against the Rockies on May 1st – they used Dexter Fowler, Alfredo Almezaga, Todd Helton, Carlos Gonzalez, and Seth Smith to get him for four runs in 5 1/3 innings. On the night, Morton walked five and only struck out one batter in large part because he was didn’t have an endless string of right-handed bats to dominate.

The NL Central is more right-handed than most divisions, so Morton will get to face fewer left-handed bats than if he played in another division, but he’s still not going to get to keep drawing line-ups where 2/3 of the batters he faces are righties. Given the types of opponents he’s faced so far, using his fastball almost exclusively does make some sense, but he’s going to have to make adjustments when he starts facing more left-handed batters.

He’s already made some adjustments as the season has gone on, but he’s going to have to continue to diversify his approach. This all-fastballs, all-the-time thing isn’t going to work against every lineup. So far, he’s gotten some favorable match-ups, but that won’t last all year, and he’ll have to do something besides pound his sinker against lefties if he wants to keep pitching well all year.

Dave is the Managing Editor of FanGraphs.

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Jon Ede
11 years ago

Well interesting article. Morton is very likely to regress, but could continue as a decent pitcher. Why not try attacking LHB with a different variety of pitches?

PS- Gabby Sanchez is a righty.

11 years ago
Reply to  Jon Ede

Whoops. Beat me to it.