Conversations with the Herd: Seattle Mariners Reliever Trent Thornton

By: Brian Frank

Seattle Mariners reliever Trent Thornton grew up in a family with a long football tradition. His father played quarterback at Indiana University, his grandfather played at the University of Kansas, and his uncle played at Davidson College. But Thornton turned to the baseball diamond instead of the gridiron when he was young.

“Just up until middle school,” Thornton told The Herd Chronicles on how long he played football. “My body was just a little too tiny for football, I think,” he chuckled.

Thornton pitched in 53 career games for the Bisons. Photo Credit: Brian Frank, The Herd Chronicles

Thornton graduated from Ardrey Kell High School in Charlotte, North Carolina, and then starred for three seasons at the University of North Carolina. He made an impact right away for the Tar Heels, going 12-1 with a 1.37 ERA and eight saves in 29 games (six starts) his freshman season. He then went 7-4 with a 2.73 ERA in 16 games (14 starts) his sophomore year.

“I would have to say my freshman year when we went to the College World Series,” he said when asked for a highlight from his his time in college.

During his freshman year, UNC advanced to the College World Series, and Thornton started an elimination game against LSU in Omaha. Thornton fired 114 pitches, allowing two runs over seven innings of work in the Tarheels 4-2 win over the Tigers. His effort helped UNC advance and ended  LSU’s season.

“Getting to pitch the elimination game against LSU on that stage was one of the cooler moments of my career,” he said.

“I think that's one of the best experiences baseball has to offer,” he added. “It's amazing.”

Thornton was selected in the fifth round of the 2015 MLB June Amateur Draft by the Houston Astros.

“One of my lifelong dreams since I was a kid was to get drafted,” he said. “Then to be one step closer to becoming a big leaguer  – so that was, at that point, one of the best days of my life.”

Thornton worked his way up through the Astros system, making it all the way to Triple-A Fresno, when he was traded to the Blue Jays during the 2018 offseason for shortstop Aledmys Díaz.

“I had just gotten home from the Fall League and within the next day or two, I'd gotten traded,” he recalled. “And, it was just kind of a whirlwind of events. I’m very grateful for the opportunity the Astros gave me, and then even more grateful for the opportunity the Blue Jays ended up giving me to become a big leaguer.”

The move proved to be beneficial for the young right-hander, as he made the Blue Jays starting rotation out of spring training. He made his big-league debut by starting the fourth game of the season against the Detroit Tigers at Rogers Centre, and fired five shutout innings, allowing only two hits and no walks while striking out eight.

“It was pretty surreal, finally getting that opportunity to call yourself big leaguer – and making the most of the opportunity was pretty awesome,” he said. “I mean, it was almost like a blur. But, it was a special day for sure.”

Thornton at Sahlen Field with the Blue Jays in 2021. Photo Credit: Brian Frank, The Herd Chronicles

He picked up his first big-league win during a start at San Francisco’s Oracle Park in a Blue Jays’ 7-3 victory over the Giants. The day was even more memorable because Thornton also picked up his first major-league hit, going 2-for-3 with two singles and two runs scored.

“It was pretty eventful, I'd say,” he smiled. “Finally being able to get my first win, and then somehow being able to muster 2-for-3 at the plate. I was almost more impressed with that. But it was crazy, because Vladdy hit two home runs and I scored both times I was on base. But, yeah, that was awesome to get those firsts under the belt.”

Getting two hits in his first interleague game at a National League ballpark might lead one to believe he had lot of at-bats in college. He didn’t – but he did bat 1.000.

“I was 1-for-1 in college,” he chuckled. “I had one at-bat against Maryland.”

After an elbow injury sidelined him for much of the 2020 season, Thornton converted to being a relief pitcher in 2021.

“I was kind of accustomed to it, because I did a little bit of that in college as well,” he said. “So, any type of role, starter, reliever, closer, I had done in college. So, it wasn't as hard to switch roles.”

After converting to the bullpen, Thornton pitched in 73 games for Toronto over the next three seasons. At the trade deadline in July 2023, he was surprised to learn that the Blue Jays had traded him to the Seattle Mariners.

“It was a kind of a blessing in disguise,” he remembered. “I got a great opportunity here (in Seattle), and the organization as a whole does a tremendous job of just getting the most out of their players. I feel like I've really started to kind of figure myself out as a pitcher a little bit more since I've been here.”

He’s made a few adjustments with his new organization.

“I would say more so philosophically,” he explained. “Just what they preach here – being first pitch strikes, winning one-one counts, and just the emphasis on that, kind of helps you focus a little bit more. So that's been something that I've really taken a liking to since being over here.”

Thornton had a 3.61 ERA in 71 relief appearances for the Mariners last season.

Thornton now pitches to one of the game’s best players – catcher Cal Raleigh. Raleigh is currently having a season for the ages. The 2025 Home Run Derby champion collected the second most home runs ever before the All-Star break, and is currently leading the major leagues with 38 home runs. He’s rapidly approaching the all-time record for most home runs in a season by a catcher – 48 by Salvador Perez in 2021. There’s no telling how high Raleigh’s home run total will climb this year.

“It's hard to put into words,” Thornton said when asked what it’s like to watch Raleigh perform on a daily basis. “He's having an absolutely amazing first half of the season. I think everyone in this locker room is just curious how he’s going to finish the year. Is he going to hit 50? Is he going to hit 60? We're all pulling for him really hard, so it's been just an absolute blast to watch.”

The Mariners went into the All-Star break coming off a three-game sweep of the Detroit Tigers and currently hold the final wild card spot in the American League. Thornton is confident the team can continue their strong play and make a deep playoff run.

“I think we have pretty much the majority of the pieces,” he said. “I think once we start really rolling, turning all the gears, we can be a very dangerous team. So, we're definitely looking forward to finishing strong before the break, and then coming back even hungrier.”