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The knuckleball has returned to Major League Baseball. From 2020-22, there were only 111 knuckleballs thrown league-wide, many by position players messing around during pitching appearances. Journeyman knuckleballer Mickey Jannis made one 3 1/3-inning appearance with the Baltimore Orioles on June 23, 2021. He threw 57 of those 111 knuckleballs that day.

For several years there, the knuckleball was going out of style and trending toward extinct, but thanks to San Diego Padres righty Matt Waldron, the pitch is back with a vengeance. The 27-year-old has a 3.46 ERA in 15 starts this season and he's thrown 525 knuckleballs in 2024. From 2019-23, there were only 501 knuckleballs thrown, 180 of which where thrown by Waldron during his MLB debut last year.

Waldron's knuckleball is becoming such a phenomenon that it's caught the attention of two-time NFL MVP and three-time Super Bowl champ Patrick Mahomes:

"The knuckleball is definitely an outlier pitch, because even if you know it's coming, there's no guarantee that you're going to get one that's good to hit," Kyle Higashioka, Waldron's personal catcher, told the San Diego Union-Tribune recently. "It's dancing out there like crazy. So regardless of whether you're looking for it or not, if he throws the good one, it's very unlikely that somebody's going to really square it up."

Waldron's knuckleball is not a gimmick pitch and he did not become a knuckleballer as a last resort, as so many in the past have. In 2023, he told Sports Illustrated he'd thrown the knuckleball since he was a kid, and the Padres encouraged him to throw it more in the minors. "I kind of immediately was like, 'OK, sounds good.' I didn't really realize how big of a commitment it was. But fortunately it's worked out," Waldron told SI.

In his last eight starts, Waldron has pitched to a 1.82 ERA and held opponents to a .184/.253/.270 batting line. He's allowed no more than two runs in all eight starts, and three times he completed seven innings. Two other times he completed six innings. Last time out, Waldron went into Citizens Bank Park and held the high-powered Philadelphia Phillies to one run in seven innings.

Matt Waldron
SD ā€¢ SP ā€¢ #61
ERA3.46
WHIP1.16
IP83.1
BB25
K76
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Steven Wright was MLB's last full-time knuckleballer, though he threw only 307 innings as an up/down swingman type with the Boston Red Sox from 2015-18. R.A. Dickey was the last knuckleballer with staying power. The 2012 NL Cy Young winner threw 1,631 innings from 2010-17, fifth most in baseball, including a five-year stretch from 2011-15 in which he averaged 219.4 innings a year. That workload seems unthinkable now. With all due respect to Wright, Dickey was baseball's last true knuckleballer.

From 2010-17, Dickey threw his knuckleball between 77% of the time (2011) and 89% of the time (2015), and filled in the gaps with the fastballs. He'd even mess around and throw a breaking ball now and then. Waldron does not use his knuckleball nearly as much as Dickey, though his knuckleball usage is on the rise, and it has coincided with this excellent eight-start stretch he's put together. Here is Waldron's pitch usage by start in 2024:

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Matt Waldron has ramped up his knuckleball usage in recent weeks. Brooks Baseball

Six of Waldron's eight highest knuckleball usage rates this season have come within his last eight starts, including five of the six times he's thrown it at least 40%. The results on the pitch are excellent. Opponents are hitting .200 with a .283 slugging percentage against Waldron's knuckleball, and they've missed with 26.3% of their swings. Those numbers compare favorably to Dickey's knuckleball during his Cy Young year: .215 average with a .343 slugging percentage and 27.6% whiff rate.

Furthermore, Waldron's knuckleball has produced an 83.7 mph average exit velocity, fifth lowest among pitch types that have been put in play at least 75 times. Only Chris Sale's slider (80.4 mph), Kyle Hendricks' changeup (82.5 mph), Max Fried's four-seamer (83.0 mph), and Tyler Anderson's changeup (83.4 mph) have been harder to square up. No other pitch is under 85 mph. Hitters miss with more than a quarter of their swings against Waldron's knuckler, and, when they do put it in play, they don't hit it hard.

"I just faced this man named Waldron and he threw a knuckleball ... Bro, deadly," Miami Marlins outfielder Jazz Chisholm Jr. said recently. "That's probably the best pitch I've seen in baseball. It's going everywhere. It goes that way, that way, that way. We were losing and I came back to the dugout and said, 'Bro, I can't be mad. The thing is going everywhere. It was a good pitch.'"

Waldron was never a highly regarded prospect. Cleveland selected him in the 18th round of the 2019 draft and traded him to the Padres as the player to be named later in the Mike Clevinger/Josh Naylor deal at the 2020 trade deadline. Waldron was the ninth player in a nine-player trade, for all intents and purposes. Only once did Baseball America rank him among his organization's top 30 prospects: No. 30 in 2022. "Waldron's repertoire was rather nondescript for a minor league righthander ... (The knuckleball) gives Waldron a chance to stand out," reads the scouting report.

Stand out Waldron has. He has been San Diego's best starter this year and he's getting better as the season progresses and he gains experience. His knuckleball is not a gimmick pitch. It's one of the most effective pitches in the game and he's gradually throwing it more often. Waldron is not a Dickey-esque full blown knuckleballer, but it is the pitch that has turned him into an effective big leaguer. So much of pitching is just being different, and no pitch in the game is more unique than Waldron's knuckler.

"Ultimately, we need five aces, but right now he's been a guy that has shut down the other club," Padres manager Mike Shildt told MLB.com after Waldron shut down the Phillies. "... We've started to see this growth of, 'Hey, I got this. 'I'm taking the next step.'"