First Pitch: Mitch Keller’s Problem Against Left-Handers

Mitch Keller has struggled against left-handed hitters so far in his MLB career.

The young Pirates pitcher has a career 13.3% walk rate against lefties, compared to 9% against right-handers. His 5.50 xFIP against lefties is two runs higher than his 3.45 against right-handers.

Keller is off to a similar start in 2021. He’s absolutely dominating right-handed hitters this season. While there was some debate about whether Keller was dominant for his start on April 10th, there’s no question that he has been dominating right-handed hitters.

This year, Keller has a 41.2% strikeout rate against right-handers, along with a 5.9% walk rate and a 1.58 xFIP.

By comparison, Keller has a 21.1% walk rate and a 6.50 xFIP against lefties. And he’s faced a lot of lefties so far.

The first outing of the season for Keller was rough, and I noticed a similar trend when he was facing lefties. Watch in the video below how often Keller misses with his fastball high and outside.

The 88 MPH pitch that got replayed a few seconds in is Keller’s changeup, and it wasn’t a good one. He’s thrown eight changeups this year, and one or two have looked good.

Keller doesn’t necessarily need a changeup, but he does need a third pitch. He doesn’t attack hitters right on with his fastball, and hasn’t been hitting the strike zone when he elevates the pitch. He has been using both of his breaking pitches against lefties, but that is only so effective when the fastball command isn’t there.

The struggles against left-handers continued into the first inning of his second start…

You’ll notice an immediate difference in this outing. Keller is yanking his pitches. In the first start, he was flying open too soon, sending his pitches sailing to the arm-side of the plate. His follow through for the first few hitters of game two was a bit extreme, but he toned it down after a few hitters. That carried over through the rest of the game…

There’s a lot to watch above. Some is promising, and some raises the same concerns that Keller showed in his first start of the season. The big highlight is the changeup in slow-mo around the 45 second mark. The GIF below:

Keller has mostly been working the high, outside corner with his fastball, and working inside with his offspeed stuff against lefties. One good changeup thrown doesn’t give Keller a weapon to work with, but if the pitch is thrown more consistently like the above, it would add some deception to those low breaking pitches, which might make Keller more effective against lefties.

Again, Keller doesn’t need a changeup to have success against lefties. He just needs the fastball to be thrown in the zone more consistently, setting up the breaking stuff.

We saw last weekend how good he can look when his game is on against lefties. We’ve seen in both starts how he can easily fall apart against lefties with poor control.

Keller could be primed for the breakout everyone is waiting for if he can fix his control issues against left-handers. That will make his next start a very interesting one to follow, to see if he continues the better results he had in the final four innings of his second start.

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