Can Zack Greinke keep this up?

The Royals starting rotation is off to an inauspicious start this season, with a 4.59 rotation ERA and 4.70 FIP that ranks them 24th and 28th, respectively, in baseball. But one bright spot has been the return of Kansas City’s prodigal son, Zack Greinke. He’s pitched admirably thus far, with a 2.67 ERA and 3.70 FIP in 33.2 innings, despite precious little run support from the offense. The way he’s going about it is very atypical for a modern pitcher; he’s essentially pitching like a dead-ball era pitcher.

Successful pitchers generally do so with good peripherals: lots of strikeouts, few walks, and few home runs allowed. Greinke has been elite in the latter two categories. His 2.2% walk rate is the fourth lowest among qualified starters, and his 0.53 HR/9 is 14th. What sticks out is the strikeout rate: 7.5%, or 2.67 K/9, easily the lowest in the majors. No one else is close; Zach Plesac and Cal Quantrill both have struck out 14.0% of batters this year for Cleveland, the second lowest rate in the majors.

No qualified starter has finished a season with a strikeout rate as low as Greinke’s since 2004, when Kirk Rueter struck out 2.65 batters per nine innings, or 6.7%, in 190.1 innings for the Giants. He walked more batters than he struck out and finished the season with a 4.73 ERA. To find the last time a pitcher struck out fewer than three batters per nine innings and also walked fewer than one batter per nine, we have to go all the way back to 1933, when Red Lucas did so for Cincinnati. He finished the year with a 3.40 ERA and 3.58 FIP, which were both around league average, in 219.2 innings.

Greinke is pitching like a man out of time; a relic of a bygone era. This is somewhat out of necessity. Greinke is 38 with over 3000 major league innings on his arm. The stuff just isn’t what it used to be. His average 4-seam fastball velocity of 88.3 mph is 7th lowest among qualified pitchers, per Statcast. The six pitchers with a lower fastball velo all also have below average strikeout rates. To compensate for the lack of velo, Greinke has changed his pitch mix:

Greinke has never been shy about changing his arsenal to find new ways to attack hitters. This year, when considering both his 4-seamer and sinker, Greinke is throwing fewer fastballs than ever. He’s also decreased his changeup usage, instead opting to throw more breaking balls.

Given the low ERA and strikeout rate, one might assume that Greinke is getting batters to swing at pitcher’s pitches, inducing soft contact. Soft contact leads to easy outs. Well...

This doesn’t exactly inspire confidence. Greinke’s xwOBA allowed is .384, which essentially means, in terms of batted ball data, batters have collectively hit like Michael Brantley against him. That’s also by far Greinke’s highest xwOBA against in the Statcast era (since 2015). His groundball rate is the lowest it’s been in that span and his line drive rate is the highest. He’s getting a lot of pop-ups, but years of evidence suggests that’s not a sustainable skill.

The deadened ball has been a boon to Greinke, with the corresponding reduced offensive environment combining with a strong Royals defense and a spacious Kauffman outfield allowing him to out-pitch his peripherals. He was snakebit by the long ball last year in Houston, but he’s allowed only two this season (one of which came in Chicago, the other being in St. Louis). He’s not the only one benefitting from the current offensive environment: out of 53 qualified starters, Greinke’s 2.67 ERA is only 18th lowest.

Something has to give here. Either Greinke needs to start missing some bats, or balls are going to start finding holes or going over the fence. The strikeout rate or the ERA must go up. Or...perhaps it doesn’t. What if the early season offensive doldrums don’t improve as the weather warms up? What if those fly balls that surely would have been homers last year continue dying on the warning track? Maybe Greinke has found the ideal way to utilize his stuff to capitalize on the current run environment.