40 in 40 2025: Trent Thornton
As one of Seattle’s rubber arms in 2024, Thornton should be poised for more of the same this year.
Quick, if you had to guess: who led all Mariners pitchers in appearances last year? Perhaps it was Andrés Muñoz, tasked with shouldering much of the late work of the bullpen with Matt Brash and Gregory Santos largely, if not completely absent? Maybe it was since non-tendered Austin Voth, brought in on an unassuming one-year deal and proved to be one of Seattle’s most leaned-upon arms? It might have even been the local lefty Tayler Saucedo, who saw plenty of left-on-left work even though the LOOGY role has been all but eliminated?
If you guessed any of those three, you’d be wrong: the reliever who led the Mariners in both appearances and innings pitched was none other than Trent Thornton. Christ. After coming over in a small deadline trade from the Blue Jays in 2023 for glove-first infielder Mason McCoy and impressing with a 2.08 ERA across 26 innings, Thornton stepped into a much larger role in 2024 as the club’s primary middle reliever, pitching 72.1 frames over 71 games, even nailing down a save against the Rays on June 26th. He proved himself to be a solid option all season, posting a 3.61 ERA and 3.47 FIP, and the homer problem that reared its head in 2023 looked to have settled down, allowing just eight all season.
Despite the solid marks and innings racked up, though, bWAR and fWAR were both a bit bearish on him last year, with bWAR especially being harsh (0.3) thanks to Thornton pitching half his games in the most hitter-unfriendly environment in MLB. fWAR was kinder at 0.6, and because WAR in general is a counting stat it’s not always the best one-stop shop for relievers, but durable, quietly effective middle relievers don’t always grow on trees, despite what the Mariners’ vaunted pitching lab has produced the last few seasons. Both FanGraphs Depth Chart and PECOTA project Thornton to take a small step back in 2025, but even if he simply matches the marks they’ve staked him out to, he should turn in another reliable season in Seattle’s ‘pen.
Projections:
Fangraphs Depth Chart: 67 IP, 0.2 fWAR, 3.73/3.95 ERA/FIP
PECOTA: 50 IP, 0.3 WARP, 3.87/4.02 ERA/DRA
Overs/Unders:
Ezra: Slightly over
Thornton has all the intangibles, the underlying stats, and the counting stats on his side. I’m always impressed with him when he comes into games, and I think he knows how to get outs consistently. One of the few consistencies in the Mariners bullpen over the past two seasons, I think we see another very solid year from him.
Kate: Under
I like Trent Thornton, I do, but he makes me nervous. I do like the adjustments the Mariners have made with his pitch mix, but to me, the foundation of any pitcher’s arsenal is the fastball, and Thornton’s just has historically gotten the snot hit out of it. To be fair, if he misses bats with it, which he does at a high rate considering how rarely he throws it, everything’s cool, but if a hitter catches up with it, not so cool. That just feels like a narrow path to dance along for success. Someone with rec specs shouldn’t cause this much agita.
Zach: Over
Yes, Kate. But the pitch-mix changes were good! I didn’t nail his 40 in 40 last year, but I was pretty insistent that he should throw his four-seamer less. And he did. And voila, he became more of a ground ball pitcher and gave up fewer dingers. More of the same would mean beating these projections.
Bee: Push
There is no doubt that I like the newer pitch mix version of Trent Thornton since he’s joined the Mariners, but for me there are still some concerns. All but two of his pitches last year had negative Run Value, but the two pitches that were in the positive (the sweeper and slider) were well in the red. And yes, he’s using his four seam less than before, but at almost 20 percent last year and his third most pitch, the heatmap is in the oven to still serve up some delicious meatballs. As much as there are concerns I have, he does have just as many encouraging peripherals, but I think the projections have it right that we’ll see less innings from him at least.