Thompson set up for multiple innings with reintroduced curveball

The Nationals have been looking to get reliever Mason Thompson stretched out to cover multiple innings out of the bullpen since late last summer. The right-hander, who was acquired in the 2021 trade for Daniel Hudson with the Padres, has previous experience as a starter that can translate to a long-relief role.

Between 2016-19 in San Diego’s farm system, Thompson started all but four of his appearances. He made 20 starts out of 22 games for Single-A Fort Wayne in 2018, pitching to a 4.94 ERA, 1.419 WHIP and 9.4 strikeout-per-nine-innings rate.

After the COVID-19 pandemic shut down the 2020 minor league season, Thompson came back in 2021 as a full-time reliever. He went 3-2 with seven saves, a 5.74 ERA, 1.238 WHIP, 8.1 K/9 and 3.00 strikeout-to-walk rate in 23 appearances with Triple-A El Paso. He only allowed one run on four hits in three innings of relief with the Padres.

Later that summer, he was traded to Washington, where he appeared 27 times out of the bullpen. Last year, he went back and forth between the Nationals and Triple-A Rochester, while only starting to go more than three outs in September.

Now the Nats are looking to continue that stretch as a multi-inning arm this season.

“I think it's just having a starter background,” Thompson said of what makes him so well-suited to pitch multiple innings out of the bullpen. “I started for most of my minor league career and then didn't get moved to the bullpen until COVID really. So I kind of have that experience of going multiple innings and I think that definitely helps me in these situations. But also, continuing to work on off-speed pitches and be able to throw those for strikes and behind the count, ahead in the count. I think that's been a big reason I've been able to have success in multiple innings.”

Thompson has made six appearances so far this season, tied for second-most in the Nats bullpen, and all but two have been for more than one inning. He’s been one of manager Davey Martinez’s most trusted arms, having a 1.04 ERA and 0.346 WHIP through his first five games before allowing three hits and one run over 1 ⅔ innings in Wednesday’s loss to the Angels.

What has helped him have so much success to start the season? The re-introduction of the curveball he used to throw as a starter.

“I've had a curveball as a starter. And then once I got moved to the bullpen, I kind of put that in the back pocket,” Thompson said. “Kind of focused mainly sinker, slider. But I've always continued to throw it in the bullpen, continue to throw it when we're throwing on the field and decided this offseason that that was going to be one of my main focuses was to kind of add that third weapon, or fourth weapon with the changeup also. It's been a good pitch for me so far.”

Thompson has only thrown his curveball three times so far. But each time it’s been effective, none more so than when he dropped one in perfectly to strike out the Rays’ Randy Arozarena back on April 3.

“I felt like I set it up pretty well the other night to Arozarena,” Thompson said. “I went four-seam up and in, which is also a pitch that I don't typically throw a whole lot. But I think kind of tunneling that four-seam and the curveball like a lot of guys do in today's game, I think that'll have a lot of success. But I still like to build off the sinker, and the sinker is gonna be the main weapon. So I think they pair well together and I've had success with both of them so far.”

Did he bring back the curveball knowing the Nationals wanted him to pitch more multi-inning outings this season?

“Partially that, but also just to show something different,” he said. “I think even if you put something else on the scouting report you only throw 1 or 2 percent of the time, it's in the back of their minds. So really, I've been throwing it, like I said, in bullpens, been throwing it on the field and a lot of the guys were like, 'Why don't you throw that in the game? It's a good pitch. It's sharp, it breaks late. It's a good pitch.' So I think kind of based on that feedback, I was like, 'You know what, let's work on it in the offseason and kind of see what we can get it to and see if it will be an effective weapon for me to use this year.'”

As mentioned, he hasn’t used that weapon too often to start the year. But as he continues to work on it and get feedback from teammates, he’ll try to incorporate it more into his outings.

“I think the more success I have with it to both sides of the plate, the more I'll throw it,” he said. “And I think right now, I'm still kind of feeling it out with nobody on, two outs or early in the count, I think it's a good weapon to use and kind of build from it. Build off of that and go from there and kind of see what the hitters' feedback is. If they're having trouble with it, then I know it's a good pitch. If they're laying off of it or they're putting good swings on it, then I know maybe there's more work that needs to be done.”

With or without the curveball, Thompson is still focused on doing whatever the Nats need him to do in order to win ballgames. And right now, that’s recording three-plus outs when the situation calls for it.

“Whatever the team needs me to do, I'm ready for,” Thompson said. “I kind of had an idea going into spring that could be part of my role. But Davey also told me during spring to be ready for anything. So whatever I can do to help the team win and put us in a good position.”