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Chris Bassitt and left-handed batters (a followup)

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I guess you can teach an old dog new tricks.

I've got thisssss much potential.
I've got thisssss much potential.
Joe Nicholson-USA TODAY Sports

It's no secret that Chris Bassitt struggled against lefties prior to coming to the A's. Alex wrote about it. Stiglich wrote about it. It, among a few other things was holding Bassitt back from being a solid starter. With the inability to get lefties out, Bassitt didn't stand a chance in the rotation but could have conceivably been a solid reliever, shielded from that weakness.

Fast forward a season from Bassitt's acquisition and the gangly righty is slated to be high in the A's rotation. Some of this is due to injuries and lack of depth, but a large part is due to Bassitt's sensational 2015 performance. In just 13 starts Bassitt was worth 1.2 bWAR, even after a rough return from a shoulder injury. How did Bassitt overcome the lefty problem?

The raw stats

Prior to 2015, lefties hit .317/.411/.381 against Bassitt in 73 plate appearances. That's a damn good line if you're a hitter. What stands out the most to me is the difference between batting average and OBP: Bassitt walked 8 hitters in those 73 appearances and hit two more for good measure. For comparison, Bassitt walked or hit a batter every 7.4 plate appearances which beats MLB 2015 walk leader Tyson Ross's rate of every 11.4 at bats.

In 2014, righties hit .250/.317/.321 against Bassitt. Again, walks were a bit of a problem in a small sample but Bassitt was clearly superior against his like handed opponents.

In the minors, the lefty/right split was always obvious. Total, lefties hit .256/.371/.408 vs. Bassitt. Righties fared much worse with a .199/.260/.286 line.

As we're all happily aware, 2015 was a much different season for Bassit, especially against lefties. Hitting a paltry .217/.313/.337 against Bassitt, lefties were actually outhit by righty hitters.

Some numbers

To tell how Bassitt has changed against lefties, let's first compare his pitch frequency from 2014 to 2015. It's important to note we're dealing with a very small sample in both seasons and splits often take time to stabilize. Still, this should give us a picture of how Bassitt attacked lefties.

The numbers below are copy/pasta'd from Brooks Baseball which is just an amazing site.

2014 vs. LHH
Pitch Type Count Freq Velo (mph)
Fourseam 58 18.71% 92.88
Sinker 75 24.19% 92.11
Change 29 9.35% 83.96
Slider 91 29.35% 84.56
Curve 56 18.06% 72.81

2015 vs. LHH
Pitch Type Count Freq Velo (mph)
Fourseam 245 28.96% 94.53
Sinker 212 25.06% 93.75
Change 103 12.17% 84.16
Slider 171 20.21% 86.73
Curve 114 13.48% 72.12

Before we dive in, I want to give my normal caveat. My analysis isn't professional (yet, I'm waiting Billy) and is very much my opinion. If you have a differing thought, please share it!

So what do you notice? First thing that jumps out is the velocity bump. Throwing harder certainly helped Bassitt against all hitters and provided he's not at increased risk for injury, should help him going forward.

Bassitt threw his fourseam fastball much more frequently against lefties in 2015, presumably to curb the aforementioned walk problem. It didn't work, as lefties still walked in north of 10% of plate appearances. Still, Bassitt threw his fourseamer 14% more while behind in the count, likely signifying a greater effort to challenge hitters. His fastball was also more effective in 2015, generating whiffs at a 10.6% rate up from 6.9% (nice) the season before. His fastball lost an inch of horizontal movement but gained an inch of vertical movement along with the MPH boost.

The next change was the increase in changeup usage, timing, and its effectiveness. In 2014, Bassitt's change was frankly a bad pitch garnering but a single whiff. Last season was different as hitters whiffed at a 6.8% rate. In that small 2014 sample, hitters hit Bassitt's change exclusively in the air via line drive or flyball. Last season was a different story as more than 50% of batted change-ups ended up on the ground.

What changed with his changeup?

Year Count Freq Velo (mph) pfx HMov (in.) pfx VMov (in.) H. Rel (ft.) V. Rel (ft.)
2015 103 12.17% 84.16 -9.02 5.01 -1.46 5.83
2014 29 9.35% 83.96 -8.87 5.6 -2.07 5.85

As you can see, the pitch itself is very similar in terms of movement from 2014 to 2015. The increased velocity is likely offset by the difference in speed between his change and his fastball/sinker. That difference has remained around 9 mph.

Interestingly, Bassitt threw his changeup for a ball more frequently in 2015, but that may not be a bad thing. As you can see from the charts below (courtesy of TexasLeaguers), he's missing his changeup below the zone more frequently (18.6% vs. 12.5% a year prior) and seems to have a higher percentage of pitches in the bottom half of the zone. If a changeup or fastball is way up above the zone, a hitter is unlikely to swing in spite of the downward movement. When Bassitt throws the ball in the zone, the downward movement will cause groundballs when batters make contact. When the ball starts in the lower half of the zone and sinks out, you'll see more whiffs. Basically, a changeup above the zone is a wasted pitch. The lowering of pitches likely explains the greatly increased whiff and groundball rate.

Bassitt Change 2014

Bassitt change 2015

Finally, the timing of Bassitt's changeups seems to have improved in a mostly positive way. He's throwing it more first pitch where hitters typically are looking fastball and might have more difficultly handling the change. He's also throwing it ahead in the count more often. I currently don't know of a way to tell a pitch value/outcome in a specific count, so there is a lot of assumption here. That said, the overall change in value of a previously bad pitch leads me to believe these usage changes have had a large effect.

The slider

In the original chart above, you'll notice a dropoff in slider usage against lefites. The slider was Bassitt's best pitch per Fangraphs (FanGraphs?) and was very effective against lefties. So why is he throwing it less? I wish I had a good answer for you to seem really smart, but I don't. I'm sure much of it has to do with the increased effectiveness in his other pitches. Some likely has to do with being efficient with such a weapon; overusing a pitch might cause it to be less effective. Interestingly, Bassitt doesn't shy away from using this pitch in various counts, likely because it's often a strike. This is an interesting and positive development for a pitcher who sometimes struggles with command. Hitters can't sit fastball/changeup first pitch with the slider being an any count weapon.

The Curve

The final piece is the curveball, which dropped 5% in usage against lefties. Fangraph's statistics rate Bassitt's curve at -1.4 runs below average, so the drop off might be a little more easily explained here. At 44.7%, Bassitt's curveball ended up being a ball more than any other pitch he threw and accordingly he threw it a disproportionate amount while ahead in the count (27%) and with 2 strikes (21%). Here's a chart of where his curveballs ended up:

There's a lot of pitches way out of the zone on that chart, and it makes sense Bassitt would decrease using his curveball fist pitch (-9%) and use it only as a pitcher's count weapon.

So what's with the walks against lefties?

Thus far, this article has been a positive journey through Chris Bassitt's changes. Unfortunately, there's still a major kink to be worked out. Bassitt walks lefties at a rate (10.4%) much higher than righties (5.4%) in spite of throwing nearly identical ratios of balls and strikes to both (38% balls vs LHH, 36% vs RHH). Why is this the case? I have a few ideas.

  1. Bassitt basically doesn't throw his changeup to RHH but does so to lefties 12% of the time as documented above. It was a very solid pitch in 2015 but it frequently missed the zone (41% of the time). As I noted above, I don't this is always a bad thing. The problem lies in the timing of the pitch: Bassitt throws it 14% of the time in hitter's counts, presumably to avoid throwing a fastball in obvious fastball counts. It's not an awful bet, as Bassitt has yet to surrender a dinger with the changeup, but it is likely causing more walks.
  2. You might be wondering what Bassitt throws in hitter's counts against righties instead of the changeup. The answer is the sinker, a pitch Bassitt throws for a ball with much less regularity against RHH (26.36%) than the change against lefties (41.75%). So why doesn't he throw his sinker against LHH in hitter's counts? Weirdly, Bassitt's control is much worse with this pitch against lefties, going for a ball nearly 44% of the time. That's an 18% increase compared to righties! My guess is lefties are less likely to swing at the sinker due to it's tailing movement. Righties are well aware of the sinker coming back towards the zone and will swing at a higher rate. Lefties likely won't be enticed by a 92 MPH weapon/sphere headed towards them, and won't swing at pitches even close to the plate since they often start off well inside. But again, that is a guess.
Going into 2016, it'll be interesting to see how this problem is addressed. As noted above, Bassitt commands his slider relatively well and it seems like a candidate to be used in hitter's counts instead of the change. This would hopefully lower the walks while still avoiding dangerous get-me-over fastballs.

At any rate, Bassitt was still effective against lefties in 2015 in spite of the walks. Hopefully he can repeat that performance and it's a nice reminder of how far from his ceiling he is. If he can cut down on those walks, his value could increase dramatically.


Regardless of the league's reaction to Bassitt's changes, his ability to adjust is huge. A large part of this is likely the A's front office, a large part is likely Curt Young. Baseball is often a game of adjustments and Bassitt has proven the ability to make a change when needed which should bode well for his future.

What does this all mean?

Again, it can't be overstated that these small samples we're dealing with here and the analysis is subjective (the numbers are all from objective sources, though). It can take years for righty/lefty splits to stabilize and with adjustments likely coming from both Bassitt and his opponents in 2016, we won't know just how effective he will be long term. That said, his ability to work with the pitching staff to make adjustments is huge and all the changes seem to be sensical and effective. Here's to a great 2016 for Chris!

Also, he seems like a dude I could be friends with due to our similar values:

Get it together, Chipotle.