Meet the Guards' knuckleballing prospect -- who's learning from a legend
5:48 AM CDT
CLEVELAND -- When baseball fans in northeast Ohio think of Tom Candiotti, they likely think of the knuckleball. Candiotti, who spent seven of his 16 big league seasons with Cleveland, is one of the most prominent pitchers to feature the offering.
That’s why Candiotti’s presence in Arizona earlier this month, at a bullpen session thrown by Guardians pitching prospect Trenton Denholm, stood out.
Denholm is among the Guardians prospects playing for the Surprise Saguaros in the Arizona Fall League this year. One of the main goals for the 25-year-old right-hander has been to continue to work on a knuckleball, as he and the organization look to see if it could become firmly part of his arsenal going forward.
“[Candiotti] was super excited about it, just to come out and help and work with me on it,” Denholm said. “He gave me some tips that have been really beneficial for the pitch itself, mostly for the strike-throwing aspect of it and being more competitive more often with it.”
Denholm began to toy with a knuckleball during his amateur career, though it was just for fun while he played catch with his teammates. He has also brought it out in those settings in the Minor Leagues, after Cleveland selected him in the 14th round of the 2021 Draft out of UC Irvine.
But given the feel Denholm showed for a knuckleball, even when just throwing off flat ground, the Guardians identified it as a pitch that could become a legit offering and another weapon in his deep arsenal.
Denholm also features a four-seam fastball (which sits in the 90-93 mph range), a changeup, a cutter, a curveball and a sinker. As a low-spin pitch, the knuckleball is unique in an era defined by high-spin and high-velocity pitches. Denholm sits in the upper-70s mph to low-80s mph range with it.
“The evolution of going from, ‘Hey, catch play, this is kind of a fun thing to just throw around and joke around about,’” Guardians VP of player development Stephen Osterer said, “to ‘Hey, let's actually get this in the game,’ I think was just the seriousness that he brought towards it over time. And [it was] us recognizing, ‘He's actually pretty consistent with this. Let’s try this out.’”
Denholm began to seriously work on the knuckleball in 2025, when he made 26 appearances (including 18 starts) with Double-A Akron and one start for Triple-A Columbus. He threw it in bullpen sessions for a month, and by the halfway point of the season he was mixing in 2-6 knuckleballs per outing.
Denholm said he always threw the knuckleball in two-strike counts or when he was ahead. He noted he had some challenge throwing it for strikes off a mound compared to on flat ground. Working with Candiotti was fruitful.
Candiotti helped Denholm make a grip adjustment, and he offered some feedback to simplify his mechanics. Those included Denholm eliminating any sideways movements and not letting his arms extend too far away from his body while he was in his delivery.
In Denholm’s ensuing Fall League appearance on Oct. 23, he allowed one run on three hits and two walks with two strikeouts over three innings. He threw eight knuckleballs -- which averaged 78.3 mph -- including five for strikes. He induced four foul balls and one flyout, which had a 90.1 mph exit velocity and went just a Statcast-projected 245 feet.
“That was the first jump I would say I had with the pitch, where I feel like it got better and I can throw it more competitively, more often,” Denholm said. “I still might have some bad days with it, where it's not really around the zone, but so far it's been pretty good.”
This past season with Akron, Denholm recorded a 3.77 ERA and a 1.19 WHIP, with 109 strikeouts and 26 walks over 126 2/3 innings. He and the Guardians will continue to gain key information on his knuckleball, such as how consistent he is with it and how hitters are responding to it. That will help determine whether it will become a long-term addition to his mix.
So far, Denholm is encouraged by his progress and what the knuckleball could mean for him going forward.
“When you throw a knuckleball, guys might buckle a little bit or be surprised and look back at you, like, ‘What the heck was that?’” Denholm said. "It just opens up the whole arsenal. … Them having that second thought about a knuckleball in the back of their head I think throws them for a loop a little bit."
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