A Numbers Game: Patrick Corbin Pitching like an Ace in Contract Year

Patrick Corbin made his first career Opening Day start on March 29 and led the Arizona Diamondbacks to a win. Zack Greinke and Robbie Ray are supposedly the D-Backs’ frontline starters. Instead, Corbin and right-hander Zack Godley have led the way.

Corbin has reinvented himself in a way on the mound and he is a better pitcher because of it. He will enter Tuesday’s start against the San Francisco Giants at Chase Field with a 2-0 record and a 2.45 ERA in three starts (18.0 innings).

So what has allowed Corbin to find his 2013 form when he was in contention for National League Rookie of the Year Award?

Pitch Mix Changes

Corbin has changed his pitch mix this season. Here is how it breaks down:

2017:

Four-seam fastball: 32.11 percent
Sinker: 21.79 percent
Curveball: 0.00 percent
Slider: 37.38 percent
Changeup: 8.65 percent

2018:

Four-seam fastball: 19.22 percent
Sinker: 30.94 percent
Curveball: 8.79 percent
Slider: 40.07 percent
Changeup: 0.98 percent

Why the Drastic Adjustment?

Corbin is throwing his four-seam fastball significantly less, his sinker significantly more, and he has abandoned his changeup while incorporating curveballs. This drastically different strategy has worked for the left-hander to this point this season.

Last season, batters hit .333 against Corbin’s four-seam fastball with a .506 slugging percentage. This season, opposing hitters are batting .333 with a .667 slugging percentage against. He has thrown fewer four-seamers this year, but you might see him throw it even less in coming starts.

Meanwhile, Corbin has thrown his sinker almost 9 percent more this year. Everybody wants to talk about Corbin’s slider and strikeouts, and rightfully so. However, while Corbin has always been a ground ball pitcher, his GB/FB percentage split has only increased.

2017: 

GB%: 50.4
FB%: 29.6

2018:

GB%: 62.2
FB%: 21.6

Batters are only hitting .238 off Corbin’s sinker, compared with a .352 average last year. Instead of always using sliders as his out pitch, Corbin has gotten out of numerous jams by using his sinker, including on Opening Night.

Bread and Butter

But of course, everybody knows that Corbin’s bread and butter pitch is his curveball. With hitters geared up to hit low-to-mid 90s fastballs more than ever before, many pitchers are simply abandoning their fastball as the primary offering and pitching to their strengths.

Lance McCullers of the Houston Astros has had a lot of success applying this concept with his curveball. For example, Corbin threw his slider over 49 percent of the time in his first start, according to Brooks Baseball and he threw it over 37 percent of the time in his next two starts.

Corbin’s best start of the year came against the Dodgers at Chase Field on April 4. In that start, he threw 53 sliders, by far the most of any pitch, and got 15 swinging strikes or a 32 percent whiff rate. But instead of throwing backfoot and backdoor sliders all the time, which he is known for, Corbin has begun to throw different variations of his slider. He will throw it when he is behind in the count and it almost looks like a get me over curveball. This has helped keep batters off balance in fastball counts. All of this allowed him to pitch 7.1 scoreless innings while giving up only one hit.

Corbin will enter his start on Tuesday with the fifth most strikeouts in the NL (29), behind Max Scherzer (38), Noah Syndergaard (33), Clayton Kershaw (31), and Carlos Martinez (30). That is some lofty company.

Corbin has induced the highest miss rate on his pitches this season, according to Sports Info Solutions. In addition, he has induced the highest percentage of swings and misses on the slider (13.93 percent) in baseball, according to Statcast. Batters are hitting .067 against Corbin’s slider and are only hitting a line drive off him 16.2 percent of the time this season, the lowest LD percentage of his career.

Corbin has pitched like an elite number one starter so far this season. If his elite performance continues, he will enter free agency as one of the youngest starting pitchers available at 28-years-old and could be in for a big payday.