Hiroki Kuroda is not going to win the Cy Young or even make the All-Star team this year, but he is quietly putting together a solid month of June with a 3.33 ERA and .509 opponent OPS over four starts (including a clunker at Oakland on June 14). That's a huge improvement over his numbers in April and May:
Let's break down his performance this month to see what he's doing right and what it means for him the rest of the season.
The Good One of the key improvements by Kuroda this month has been his ability to limit hard contact. He has a line drive rate of 18 percent in June, compared to 24 percent in the first two months. Also, only 15 percent of at-bats against him have ended in a hard-hit ball, a decrease from his 20 percent hard-hit rate in April and May.
Kuroda's home run rate may not be sustainable, with one homer allowed in 24 1/3 innings in June after giving up nine in 65 innings in April and May. Yet it's worth noting that his flyball distance is down more than 20 feet this month (258 ft) compared to the first two months (281 ft), which helps keep the ball in the park.
His pitch mix hasn't changed at all but his signature splitter is finally showing some bite. After opponents hit .264 in at-bats ending in Kuroda's splitter in April and May, they have zero hits in 17 at-bats against it in June.
Sixteen of the 19 outs he's recorded with the pitch have been via grounders or strikeouts, and just one of the 90 splitters he's thrown in June has been hit hard.
Kuroda's splitter also has more movement this month, with an additional inch of horizontal break and a half-inch more vertical break compared to the first two months of the season.
The Bad Despite these promising statistical improvements in June, there are a few reasons to question whether Kuroda can keep this up.
Kuroda's command and peripheral stats are significantly worse this month compared to the rest of the season. His walk rate in June (7.6%) is nearly double that of April and May (3.9%), and his strikeout rate has decreased. Batters are also making more contact against him and he's getting fewer hitters to chase pitches out of the zone.
Although he's limited his rate of hard-hit balls in play this month (which often leads to a decrease in BABIP), his BABIP of .214 is more than 70 points below his career average (.285) and likely to regress.
Another sign that he's been lucky this month is that his xFIP (a defense-independent ERA estimator which regresses home run rate) in June (4.07) is actually higher than it was in April and May (3.63).
The Ugly Finally, the Rogers Centre in Toronto has been a house of horrors for Kuroda during his career. He is 1-3 with a 5.65 ERA in five starts at the ballpark, his third-worst ERA at any venue where he's started more than two games.