Mariners’ Jackson Kowar Being Evaluated For Possible Arm Injury

The Mariners’ bullpen has already had its share of injury scares this spring. Fear of a monthslong absence for top setup man Matt Brash has been alleviated with a diagnosis of inflammation in his right elbow, but he’s weeks behind schedule now and will be built up cautiously. Trade acquisition Gregory Santos was shut down for a week earlier this spring due to a lat issue but has resumed throwing and could yet be ready for Opening Day, though that’s contingent on him avoiding any further setbacks of course. Now, Mariners manager Scott Servais tells reporters that right-hander Jackson Kowar is meeting with a doctor tomorrow to have his arm evaluated (X link via Ryan Divish of the Seattle Times).

That may not seem like a significant concern, given Kowar’s unsightly big league track record. The former Royals first-round pick and top prospect was traded to Atlanta and then to Seattle in a pair of change-of-scenery swaps over the winter. He’s 27 years old and, in parts of three big league seasons, has yielded more than an earned run per inning (75 runs in 74 frames). He also has a minor league option remaining. On paper, he looked like a long shot to make the team.

But as Divish recently wrote, Kowar has impressed the Mariners in camp. He’s averaged 96.1 mph on his heater in his career but was hitting 98 mph early in camp. Kowar has pitched a pair of scoreless innings, fanned three of his six opponents, and caught the team’s attention with the quality of his changeup. With Brash unlikely to be ready for the opener and Santos also still building up, there was a potential spot for Kowar to claim. Divish noted that he had “seemed to be locking in a spot” before soreness in his arm led to a temporary shutdown. Kowar last pitched on Feb. 28 and is now going for additional testing — an ominous sign.

The Mariners have a knack for unearthing bullpen talent. In the past few years they’ve turned unheralded pickups of Paul Sewald, Drew Steckenrider, Justin Topa, Kendall Graveman, Gabe Speier, Tayler Saucedo and others into impact moves. Their ability to find hidden gems to round out the relief corps has allowed the M’s to perennially field strong bullpens and also to avoid the types of multi-year deals for relievers that often turn into landmines. A few short looks in spring training is far too small a sample to indicate Kowar would be the next bargain find for president of baseball operations Jerry Dipoto and his staff, but at the very least, the hard-throwing Kowar was trending in the right direction. At least for now, that’ll be put on hold — hopefully only for a brief period.

Already dealing with a trio of arm scares in the bullpen isn’t an enviable spot to be in — particularly since Seattle traded one of last year’s top setup men, the aforementioned Topa, to the Twins as part of their trade to acquire second baseman Jorge Polanco. The Mariners still have one of the game’s most talented closers in righty Andres Munoz, and they can look to lefties Speier and Saucedo to build on last year’s breakout showings to help form a setup corps. Santos could be ready for Opening Day still, and if not, he and Brash may not be delayed all that long.

But the Mariners were already likely to be relying on some unproven arms — Kowar among them. Righty Trent Thornton had a strong showing after coming over from the Blue Jays in a little-noticed trade last year. Flamethrower Carlos Vargas, acquired in the Eugenio Suarez trade, has a significant ceiling but worrying command issues. Swingman Austin Voth has had flashes of big league success but has lacked consistency. Former eighth-rounder Ty Adcock had a solid debut in ’23, but last year’s 15 2/3 innings in the majors were his first experience above Double-A. Offseason pickups of Mauricio Llovera, Collin Snider and Cody Bolton give the M’s some other options, but none are proven at the big league level. Veterans like Heath Hembree, Ty Buttrey and Trevor Kelley are in camp on non-roster deals.

The Mariners likely wouldn’t shy away from late-spring additions, be they via the trade market, the waiver wire or perhaps a late splash for one of the remaining free-agent relievers of note (e.g. Ryne Stanek). Even in the absence (so far) of a major injury, their depth is already being tested a bit.