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Master · 1984-2007 · right-handed

Roger Clemens

The only pitcher with two twenty-strikeout games, built late on a splitter he called Mr. Splitty.

Signature pitchSplit-finger fastball

Clemens started on a mid-90s fastball and a ferocious, confrontational presence, then in the 1990s added the split-finger he jokingly nicknamed "Mr. Splitty" and made it his out pitch. He is the only pitcher in history with two twenty-strikeout games in nine innings.

01The signature pitch

From the 1990s on, the strikeouts ran through a split-finger fastball he nicknamed "Mr. Splitty." It left his hand looking like the fastball and dropped off the table late, the wide grip killing the backspin that keeps a four-seamer riding.

Reputable analysisWikipedia, Roger Clemens

The nickname and the splitter’s role are documented on Wikipedia; the "Mr. Splittee" spelling sometimes seen is a typo. No Clemens-specific splitter tracking data exists for most of his career.

Study the splitter
The Splitter seam, oriented to its spin axis.

The splitter seam, our own schematic

02The mental edge

Clemens drew a hard line between game day and every other day, cultivating an unfriendly, intimidating presence on the mound that he called motivation, not anger. Strikeouts, he said, were a situational tool to apply pressure, not the point of every at-bat.

If someone met me on a game day, he wouldn’t like me. The days in between, I’m the goodest guy you can find.
Pitcher's own wordsESPN Classic, Clemens thrives on confrontation

Said in 1990 with the Red Sox, on his game-day persona.

03The record
Career wins
354
Career strikeouts
4,672
Cy Young Awards
7

1986, 1987, 1991, 1997, 1998, 2001, 2004. A record.

20-K game, April 29, 1986
20 K, 0 BB, vs. Seattle

The first nine-inning 20-strikeout game in MLB history.

20-K game, Sept 18, 1996
20 K, 0 BB, vs. Detroit

Tied his own record; his last win in a Red Sox uniform.

Filed the way every record here is: each figure season-stamped where it applies, confidence-labeled, and one click from its source. Where the reputation and the data disagree, the gap is shown, not smoothed over.