FINAL GRADES: Trent Thornton Could Factor Into Seattle Mariners 2025 Plans
The Seattle Mariners will have a lot of decisions to make in 2025.
On top of having to figure out three-of-four infield spots, the Mariners also have several bullpen spots to sort through.
Seattle will have reliever Matt Brash back in the fold by June or July next season and Gregory Santos will presumably be fully healthy by next season barring a setback.
Those two will rejoin high-leverage arms Troy Taylor, Collin Snider and Andres Munoz. As for who else will be in the bullpen, that's a different question.
Gabe Speier, JT Chargois, Trent Thornton, Austin Voth and Tayler Saucedo are all arbitration-eligible in 2025.
Some of those hurlers will return and others will get non-tendered.
But Thornton's second-half of 2024 might have been enough to keep him in the Pacific Northwest.
Trent Thornton by the numbers
Pitching stats: 3.61 ERA, 71 appearances, 4-3 record, 72.1 innings pitched, 77 strikeouts, 1.13 WHIP, 1 save, .238 opp. BA, 0.3 WAR
Advanced pitching stats: 3.32 xERA, .229 xBA, 32.6% Chase, 27.1% Whiff, 3.47 FIP, 9.58 K/9, 72.6% LOB
What I liked
Thornton has an extremely diverse pitching arsenal for a reliever. But given the fact that he made his major league debut as a starter in 2019 with the Toronto Blue Jays, that's not too surprising.
According to Baseball Savant, Thornton threw a sweeper, slider, four-seam fastball, curveball, sinker, cutter and change-up in 2024.
Thornton threw his sweeper and slider at a 30.3% and 21.7% rate, respectively. He threw his fastball just 20% of the time for comparison.
Trent Thornton, Frisbee 79mph Sweeper. 🥏
— Rob Friedman (@PitchingNinja) September 9, 2023
21 inches of horizontal break. pic.twitter.com/H4yUdpFubY
Contrary to most pitchers, Thornton used his off-speed and breaking pitches to get ahead in pitch counts and used his fastball to sit down batters.
Thornton had a 29.2% put-away percentage and generated a 30.6% whiff rate with his fastball. The pitch with his second-highest put away rate was his slider at 20.3%.
Thornton also bounced back from a disappointing first half.
Thornton had nine appearances in July totaling 10.1 innings. He allowed 10 runs (eight earned runs) and his ERA ballooned to a season-worst 4.44 by the end of the month.
Thornton allowed five earned runs total in the final two months of the season and brought his ERA total down to 3.61.
Best game
Thornton was used in a variety of roles in 2024. He was used as a high-leverage arm in the final inning, was the first pitcher out the bullpen when the starter was pulled early and was sometimes the first pitcher reliever on the mound when the team was trailing.
With such a variety of roles for Thornton, it's unfortunate that his best game probably came in a loss.
Thornton pitched 1.2 innings in a 4-3 loss against the Tampa Bay Rays on June 24. He pitched 1.2 innings and struck out three batters while allowing no hits and giving up just one free base via a hit batter.
Future prospects
As mentioned before, Thornton is up for arbitration in 2024.
Thornton is projected to earn $1.35 million in arbitration according to Spotrac. At that price, it's likely that the former Blue Jay will be extended a qualifying offer and will be back for 2025. Especially with how he closed out the year.
With Brash, Santos, Taylor, Snider and Munoz all capable of being high-leverage relievers, the Mariners need to have arms that can give those aforementioned players a rest. They also need arms for low-leverage spots.
Thornton proved himself capable of a variety of roles for Seattle. His past as a starter can also help the team on the (very) rare occasions where they have bullpen days.
Final grade: C-plus
Thornton breaks the streak of pitchers earning a "B" grade or higher, but it's mainly due to circumstance.
Thornton's ERA was inflated during the first half of the year. But when you take into account his role as a low-leverage arm, and the offense's bad habits of wasting quality outings from their starters, there were a lot of situations of Thornton entering the game in blowouts or inheriting runners.
That's not disregarding the struggles Thornton had. According to Baseball Savant, hitters averaged at least a .260 average or better in four-of-seven of his pitches (fastball, curveball, sinker, change-up).
But Thornton seemed to find a comfortable spot in the last two months of the season. And if he does come back with five high-leverage arms ahead of him, as is to be expected, then he will likely be just fine in 2025.
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