A Look at Chris Sale's Dominant Stretch

Chris Sale has been shutting hitters down, and he owes that to the return of his signature slider.

Chris Sale, the Chicago White Sox ace, is holding a streak of seven consecutive starts where he has racked up 10 or more strikeouts. Over that stretch, he has 85 strikeouts and only 8 walks, along with a sparkling 1.90 ERA and 1.16 FIP.

From May 23 to June 8, he totaled 97 swings and misses across four starts, becoming the first pitcher since the Big Unit, Randy Johnson, in 2002 to force at least 20 swings and misses in four straight starts, according to the Elias Sports Bureau.

We've known Sale to be an elite pitcher for some time now, but he has really stepped up his game recently.

Worry for Naught

Although it seems strange to think now, there was reason to worry about Sale earlier this season. After returning from a broken foot on April 12, he posted two great starts (by most pitchers’ standards, anyway) before holding the contact-happy Kansas City Royals to two runs over seven innings, albeit with only two punchouts.

Then, he got shelled in consecutive outings, allowing nine runs in 3.0 innings at Minnesota and five runs in 5.1 innings versus Detroit. There was some freaking out at that point, but let’s not forget that the Minnesota Twins have been sneaky good both at home and against southpaws and that the Tigers are one of the best teams in baseball against lefties with a team .342 wOBA this season

According to FIP and xFIP, which aren't ideal when looking at one-game samples, Sale just didn't pitch that well in those two games. Everyone has an off day once in a while, and in hindsight, it might have been that because after the Detroit start, he turned things around with his first double-digit strikeout game of the season on May 12.

Better Slider, Better Results

Did Sale’s broken foot hamper his early-season performance? I don’t know.

However, I do know that in Sale’s first five starts after returning to the White Sox, he didn’t have his best stuff. Check out the difference between the versions of Sale’s slider we saw during the periods when he has struggled (the first one) and flourished (the latter column).

First Five StartsNext Nine Starts
Slider Velocity81.5079.81
Horizontal Movement (in.)-3.39-5.84
Vertical Movement (in.)-2.04-3.03

That slider is Sale’s signature pitch, and even though he has dialed back his usage of the pitch in favor of the changeup to try to stay healthy, it keeps batters on edge. One of Sale’s best qualities as a pitcher is that he gets so much movement with his pitches that he is tough to predict. (Just cite the stats above.)

With this below-average slider, hitters could keep up with the pitch and had success, racking up six hits versus only four strikeouts in 14 at-bats ending with the pitch over his first five starts.

In his nine most recent starts, however, the pitch was almost two miles per hour slower had more vertical and horizontal break. Now, in 30 at-bats ending with the pitch, he has 24 strikeouts and six hits allowed.

The reversion of the slider to 2014 form also led to better performance from Sale’s three other pitches. He has induced more whiffs on every pitch. Below, check out the whiff percentages for his respective pitches. Whiff percentage increases across the board.

First Five StartsNext Nine Starts

While swing percentage against the slider has decreased from 58.33% to 41.24% since the pitch has improved, the swing rates have increased for all other pitches. It has been especially helpful to keeping hitters off the changeup.

One pitch can make a difference, as we've seen. With the slider back at the "nasty" classification, Sale is pitching about as well as he can.

Going Forward

Can Sale sustain his 18.2% swinging strike rate that he has carried in his last nine starts? Given that Clayton Kershaw led the big leagues with a 14.2% swinging strike rate in 2014 and has increased that figure to 15.6% this season (a career high for the Dodgers ace), it doesn’t look like Sale can keep it up to quite the same levels.

If that happens, his strikeout rate will regress from 40.4% toward his career mark of 28.1%, although there is reason to believe that with the dominance he has had, his strikeout rate will be closer or greater than the 30.4% he had last season, when he finished third in the AL Cy Young voting.

If he avoids the injury bug over the rest of the season, Sale will likely surpass 200 innings pitched for the second time in his career. If that happens with this type of performance, he will likely push past Chris Archer, Sonny Gray, David Price, Dallas Keuchel, and others for the Cy Young.

The Steamer projection system has Sale pegged at 272 strikeouts by season’s end, and that would be more than any other pitcher from 2014 (and just shy of Yu Darvish’s 277 from 2013).

And our algorithms project Sale to rack up 115 more strikeouts this year, more than any other pitcher from here on out.

Meet ‘‘apex’’ Chris Sale, everybody.