Blake Snell’s disappearing fastball

Blake Snell has not been good recently. In four starts this month, Snell has posted a 10.29 ERA, 4.83 FIP, and 4.91 xFIP. Of the four, only one start was anything near quality, when he held the Boston Red Sox to one run in 6.0 innings on June 9. In the other three, he hasn’t gotten through the fifth, and most recently, he got only one out against the New York Yankees while walking four.

Overall, this season feels like a let down after winning the AL Cy Young last season. In all likelihood, any followup season was going to feel disappointing after posting what will likely be a career-best 1.89 ERA.

The ERA is massively different, up almost 2.50 runs per nine. The BABIP is up and the home run rate is up. That’s never going to lead to better results. A sub-.250 BABIP like he posted in 2018 isn’t likely for anybody. His strikeout and walk rates are nearly identical and leads to having nearly identical xFIPs.

After the last few outings, it’s surprising to see his walk rate is marginally better than last year, considering he has walked eight of his last 26 batters faced.

So what has been different?

Despite the near identical peripherals, Snell’s pitch mix has changed quite noticeably from 2018 to 2019.

Sliders are down and changeups are marginally down. This is mostly a product of the handedness of batters faced. Snell hasn’t thrown a lefty vs lefty changeup since 2017, and his slider rate to right handed batters has held below 5%. Teams have shielded their left handed bats against Snell more frequently this year, as the amount of lefties faced has fallen from 19.5% to 14.8%. This explains the slider and changeup mix.

The fourseam and curveball mix is where things have actually changed on a process basis. Snell has dropped his fastball rate roughly 10%, with almost all of that going to his curve. Snell’s curve is a great pitch, so it’s only natural to want to throw it more. The results haven’t been nearly as good (.170 batting average compared to .126 last year) especially with five homers allowed compared to just one a year ago.

When is Snell throwing his curveball more?

When Snell is ahead or has two strikes on a hitter, the curveball is his go-to pitch. There are minor differences in his usage between last year and this year. His curveball is used as his put-away pitch of choice, and with a 25% swinging strike rate on the pitch, it seems like a very good choice.

The first thing that jumps off the chart is Snell’s first pitch curveball rate. Going from 14% to 37% is a massive change. A first pitch curveball is far different than in any other situation. The pitch needs to be thrown in the zone. You aren’t trying to get a swing, because batters just don’t swing at the first pitch that often.

Outside of 3-0 counts, there is no other count that a batter is more willing to take a pitch. The difference between 0-0 and any other count is vast. You’ll get almost 50-100% more swings in almost every other count.

Forty-two of Snell’s 108 first-pitch curves have resulted in falling behind in the count. Thirty-two of the pitches have resulted in a swing, and he’s allowed two homers. Batters are swinging at an average number of his first pitch curves. Snell is throwing it enough that batters aren’t surprised by the pitch coming on 0-0 anymore.

Last year, players took more of the curves and Snell threw it for a pitch strike almost 70% of the time. Only two players put a first-pitch curve in play, and neither of those resulted in a base hit allowed.

The other situation that Snell’s curveball usage has substantially increased is when the batter is ahead or the count is even.

Moving forward

While the last few starts haven’t been ideal Blake Snell is still a great pitcher. He needs to fine-tune his pitch selection, and more importantly, when he throws his best secondary pitch.

Snell should take a look at Charlie Morton’s usage. When he’s ahead or has two strikes, Morton throws his curve just over 50% of the time. Snell’s third pitch (changeup versus righties and slider versus lefties) is better than Morton’s, so he doesn’t necessarily need to increase the usage in these spots. A few extra percent wouldn’t hurt, though.

As a first pitch, Morton doesn’t feature his curveball all that often. His 20% rate is a little higher than Snell’s 2018 rate. Snell has a very good fastball. Hitters hit fastballs better than almost all secondaries, but the first pitch is when you can exploit a hitter’s lack of aggression with a fastball to get ahead in the count.

Snell’s fastball is still very good. He’s throwing it for strikes more because he has to than he wants to right now because of falling behind when players don’t chase breaking balls as often when they aren’t in a count that forces them to.

On some days, it does makes sense to throw more early-count secondary pitches if hitters are being aggressive.

Snell’s 2019 has been quite good outside of the homers and some bouts of losing of command. As we can see, there are even areas (not particularly hard to find) where he can improve and take it to an even higher level than 2018 when it comes to process (FIP/xFIP) if not results (ERA).