Guardians Sign Colin Holderman: a Breakdown

Way back at the non-tender deadline towards the end of November, the Pittsburgh Pirates non-tendered reliever Colin Holderman. Today, for $1.5 million, Holderman is a Guardian.

Holderman is a big right-hander, standing at 6-foot-6. He releases from a ~30 degree sidearm slot with the capability of pumping out 98-100 mph sinkers. He has a sweeper that breaks nearly a foot horizontally and nearly three feet down, and his newly found, hardly used splitter saw whiff rates near 40% in its infancy. This all sounds really promising for a fourth year man trying to find footing in the bullpen. Holderman posted a 7.01 ERA in 25.1 innings in 2025 with a K-BB% of just 1.6%.

It’s easy to see why Holderman was non-tendered. What’s harder to see is how it got to that point. A solid 2024 that saw Holderman’s best season as a big leaguer had the Pirates feeling as if they had a solid middle innings bullpen guy. Holderman posted a 3.16 ERA to go with a 77% left-on-base rate in 2024. Holderman inherited 23 baserunners in ‘24 with just 6 scoring. That comes out to a respectable 26% rate. However, an issue that plagued Holderman in 2024, and his whole career in fact, was a ballooning 11.2% walk rate. That rate jumped to 12.6% in 2025. The much larger, substantially more concerning number was that Holderman’s strikeout rate plummeted from 25.1% in 2024 all the way down to 14.4%.

Holderman possesses very good stuff. Stuff+ on Fangraphs graded Holderman out with an above average sinker (112), sweeper (133), and cutter (105). TJStats had them all above average as well, so what happened that took a 25.1% strikeout rate down to 14.4% if he improved his arsenal?

It all starts with an injury, as it often does. A knee sprain sidelined Holderman for a portion of the early season, and then in late May, Holderman dealt with right thumb inflammation that ultimately cratered his 2025 season. The inflammation wound up being tenosynovitis which, long story short, is similar to tendinosis. Essentially, gripping the ball was very painful for quite a while, and the only two ways to work around it are rest or surgery, if necessary. It likely would explain why his sweeper location plot went from the left picture in 2024 to the right picture in 2025:

After returning from the IL in late April from the knee sprain until returning to the injured list in late May for the thumb injury, Holderman posted an 8.71 ERA with 7 walks to 5 strikeouts. After returning, Holderman’s numbers improved, but his control did not. He lived in the heart of the zone with his sinker, and he just never regained feel for his sweeper. He was eventually demoted to Triple-A to finish the season.

So, what can we expect from Holderman in 2026? For starters, a clean bill of health. That is priority number one. Ensure his thumb is okay, and go from there. Tendinitis and tendinosis can always flare back up, but if taken care of correctly, it can be mitigated.

Secondly, continue figuring out what’s there with the splitter. Though Holderman’s splitter doesn’t differ a ton from his sinker’s movement plot, its usage becomes very important against left-handed hitters in creating the handedness platoon neutralizer. Holderman threw his newly found splitter just 9.8% of the time to lefties, but it generated a 40% whiff rate across 10 swings with just two being put very weakly into play. It’s a new pitch, and he didn’t throw it at all after returning from injury. Whether it played a part in him getting hurt or if he dropped it as he was slowly working himself back into game shape is unknown, but once Holderman returned, lefties hit just .154 with a 31.3% overall whiff rate. Add in continued development, and Holderman can almost drop his sweeper from his LHH arsenal entirely and work exclusively sinker/splitter/cutter.

Speaking of the sweeper, I expect his to return closer to form almost right away. A full offseason of work with the Guardians’ pitching development staff in Arizona plus Carl Willis and Brad Goldberg make me trust that he will right that ship. The key is keeping it down and away to right-handed bats and as a backdoor weapon to lefties early in counts to steal strikes. Where Holderman had issues, if we reference the above graphic, was burying it like he was able to in 2024. His sweeper possesses quality stuff, and it can be a valuable weapon inside to right-handed hitters in a similar vein as a backup slider, but it’s vastly more effective when he prioritizes whiffs with it down and away. Holderman’s sweeper in 2024 had an opponent average of just .163, an xwOBA of .216 with a 40.1% whiff rate. It was among the better sweepers in baseball, ranking fifth in all of MLB in run value with +6 RV. That drastically fell off in 2025 (-7), and location tells the story. A good comparison here is Tanner Houck, but as a reliever. When you can’t locate your sweeper down and away, a lot of its deception deters its stuff, and when it gets hit, it tends to find grass or bleachers.

Holderman’s walk issue likely maintains, though getting it under 10% would be ideal. Cleaning up his sweeper and his handedness splits also helps this while in turn helping the strikeout rate get back to it’s normal numbers. Holderman will come to Cleveland with two minor league options remaining, so a chance to be patient with him as he gets acclimated with the org is there. All in all, this is a quality depth signing with high upside, and given the cost, a very team-friendly deal as well. Here’s to hoping they’re not done with the bullpen yet, either.