Apparently 10 is the magic number for Corey Kluber.
The outing marked Kluber’s second 10-strikeout performance in the past week, and he’s now fanned exactly 10 batters in four of his last six starts. Overall, it was Kluber’s eighth start this season with double-digit strikeouts.
Kluber, 28, has been nothing short of dominant since the All-Star break, pacing all starting pitchers with a 0.76 ERA, 0.69 WHIP and 55 strikeouts over 47.2 innings. On top of that, the right-hander has allowed just 27 hits, none of which have left the park, and six walks during that span.
Though he was already enjoying the best season of his four-year career, Kluber’s second-half success has thrust him into the discussion as one of baseball’s elite starting pitchers.
"He's getting an air about him like a Nolan Ryan or a Roger Clemens," pitching coach Mickey Callaway said to Jordan Bastian of MLB.com. "That's what I feel like when he's on the mound. I feel like one of those guys is pitching right now."
Take one look at the AL pitching leaderboard and you’ll see what Callaway means.
Kluber’s 2.41 ERA is the third lowest among qualified starting pitchers this season, behind Felix Hernandez and Chris Sale, respectively, while his 197 strikeouts rank second to David Price’s 205.
More importantly, Kluber’s 5.2 fWAR entering Friday ranked third across starters in both leagues over a slew of Cy Young candidates including Clayton Kershaw (5.0), Sale (4.7), Max Scherzer (4.6) and David Price (4.0). The only pitchers with a better WAR than Kluber this season are Hernandez (6.2) and Jon Lester (5.4).
So, what exactly has made the Indians right-hander so dominant this year?
For starters, Kluber has mastered the feel for his sinker, a pitch he first started to mess around with in 2011 at Triple-A Columbus.
"I'd never really thrown it much on a consistent basis," Kluber said, per Bastian's MLB.com report. "I'd throw my four-seam and, here and there, I'd mix in a two-seam. After I threw it over and over and over and over, and it kind of clicked. It was like, 'This feels a lot better.'"
Kluber has thrown his sinker 49.53 percent of the time this season, according to Brooks Baseball, which is consistent with his use of the pitch from 2013 (49.89 percent).
However, he’s throwing it harder this season—his velocity has steadily increased in each of the past four seasons—sitting above 94 mph (94.39 mph to be exact) for the first time in his career.
The uptick in velocity has reduced the vertical action on his sinker, but it’s also allowed him to more effectively command the pitch to both sides of the plate. As a result, Kluber is inducing whiffs at a career-best rate this season (4.76 percent) and generating significantly fewer fly balls.
Kluber’s sinker also has done wonders for his secondary pitches, which are nasty offerings to begin with.
Just how nasty? FoxSports.com's Gabe Kapler feels they're so good that command is of secondary importance: "His stuff is so nasty, with such devastating late movement, that he can miss badly over and over and get away with it."
Hitters are now aware that Kluber can pitch to both corners with his sinker, and it has in turn made them more susceptible to his cutter and slider. The result has been roughly a four percent increase in his whiff-per-swing rate with both pitches.
Kluber’s 34.38 percent whiff-per-swing rate with his cutter—developed in 2011 along with his sinker—currently ranks first among all starting pitchers (who have thrown the pitch at least 200 times this season), and he checks in 10th for his slider at 43.52 percent, per Baseball Prospectus’ PITCHf/x leaderboards.
Meanwhile, hitters have posted a .072 average and .098 slugging percentage against Kluber’s slider this season, which are the lowest opponents’ averages for that specific pitch in the major leagues among qualified starters.
What Kluber has done this year has nothing to do with luck; over the last four years, the right-hander has steadily evolved into the pitcher he is today—an elite one.
If his performance over the rest of the season is anything close to what he’s accomplished so far, Kluber should challenge King Felix and Chris Sale for the AL Cy Young.