“Baseball has done nothing, given no direction, for an alteration in the baseball,” he said at the All-Star Game last month.
That hasn’t appeased many pitchers.
For so long, Tanaka has placed his index and middle fingers along two seams of the baseball to throw his splitter, while other pitchers spread their fingers farther out. This season, Tanaka said, he has noticed a difference in the seams, and thus the behavior of the splitter.
“It’s not giving you the vertical drop,” he said.
Tanaka’s splitter dips less downward and more sideways this year compared with previous seasons, according to BrooksBaseball, a pitching analytics site.
“It looks more like a two-seamer,” Tanaka said, referring to an entirely different pitch.
The result: Opponents are hitting .292 against Tanaka’s splitter, a career high. They hit .191 against his favorite pitch in 2017 and .220 in 2018. Of the 21 home runs Tanaka has allowed this season, eight have come off splitters, more than off any of his other pitches.
He managed to earn an All-Star spot, but his performances since the break have slipped, and his confidence in the splitter has clearly wavered, too. In his July 25 start against the Boston Red Sox, Tanaka surrendered a career-high 12 runs in three and one-third innings. He threw only four splitters, matching a career low, and the Red Sox whiffed at none of them.
Tanaka, a right-hander, has relied more on his four-seam fastball and his slider, which has been his best pitch this season and does not require him to rely on the seams.