DETROIT – The Detroit Tigers have several exciting young pitching prospects in the minor leagues, but it's a member of the major league rotation who has showed the most promise so far this season.
While Casey Mize, Matt Manning, Alex Faedo and Beau Burrows dominate minor league hitters en route to Detroit, Matthew Boyd is already doing the same against MLB lineups.
In fact, after another strong start over the weekend, Boyd is the most valuable pitcher in baseball, according to wins above replacement.
With a 1.6 WAR, Boyd ranks just ahead of James Paxton and Max Scherzer, who have also made six starts. Even Luis Castillo, Tyler Glasnow and Trevor Bauer, all off to incredible starts, can't match Boyd's current WAR.
How is Boyd, at age 28, seemingly taking an ace turn after a solid, but unexceptional, career season in 2018?
The most obvious sign of improvement has been Boyd's ability to miss bats. Not only does he rank fourth in MLB with 48 strikeouts, he's among the elite strikeout pitchers in terms of swinging strikes.
Boyd trails only Blake Snell, Max Scherzer, Gerrit Cole and Caleb Smith -- three of the league's best pitchers and an elite bat-misser -- in swinging strike percentage.
Through six starts, 15.6 percent of Boyd's pitches have resulted in swings and misses.
While these strikeout rates will likely regress throughout the season, Boyd has clearly made a significant improvement for a second-straight season.
Last year, Boyd posted a career high with 8.4 strikeouts per nine innings. This year, it has ballooned to 11.6 strikeouts per nine innings.
Even if Boyd finishes closer to a strikeout per inning, he could be a top-of-the-rotation starting pitcher for the Tigers.
Ground ball rate
If missing bats is the most important skill for pitchers, keeping the ball on the ground is second.
During the fly ball revolution, home runs are at an all-time high, and they've been an issue for Boyd at times in his career.
This season, however, he's posting a career high ground ball rate of 39.1 percent -- more than 10 percent better than last season. For a pitcher who allowed 27 home runs in 31 starts last season, that improvement is nearly as significant as the strikeout rate.
Boyd's line drive rate is nearly identical to last year's, so that 10 percent rise in ground ball rate is coming entirely out of his fly ball rate.
Again, he's only six starts into the season, so Boyd's ground ball rate could certainly drop. But he's currently closer to his career MLB rates than he was last season.
More strikeouts and fewer fly balls is the exact formula Boyd needed to take an ace-like turn.
Boyd is doing pretty much everything right so far this season, but he's also benefited from a bit of good luck.
Most notably, Boyd hasn't allowed enough home runs, even considering his decreased fly ball rate. In his career, Boyd has allowed home runs on 12 percent fly balls, including 11.2 percent last year.
This season, that number is down to 5.7 percent -- less than half his career mark. Boyd showed a similar trend early last season, but the percentage normalized by the end of the season and his numbers suffered as a result.
Boyd is inducing more soft contact so far this season, which can account for some of the improvement. But his hard contact rate is right on his career mark, so eventually the home run to fly ball rate will rise.
Boyd's strand rate (69.9 percent) and opposing BABIP (.292) are also very similar to his career levels, so the home run rate is the only major regression that seems inevitable.
Can Boyd be an ace?
So far, everything Boyd's done, other than the home run rate, looks sustainable, to an extent. His swinging strike percentage supports his strikeout rate and his improved ground ball and weak contact rates increase the margin for error when the ball is put in play.
Chances are Boyd will finish the season with an ERA higher than 3.13, a WHIP higher than 1.02 and a strikeout rate lower than 11.6 per nine innings.
But with the clear improvements he's made, Boyd is proving he can not only stick in the rotation long term, but be near the top of that rotation, even when the likes of Mize and Manning start knocking on the door.