Washington Nationals’ 2023 Bullpen: Mason Thompson an intriguing option for ‘pen…

Acquired from San Diego (along with infielder Jordy Barley) at the trade deadline in 2021, Mason Thompson, a 3rd Round pick in 2016 who’d debuted with the Padres earlier that season, got 27 appearances in with Washington’s Nationals down the stretch late in ‘21 (4.15 ERA, 5.71 FIP, 14 walks, 21 Ks, and a .308/.406/.484 line against in 21 ²⁄₃ IP).

Thompson, 24, suffered a right biceps strain early in 2022, which limited his time in the majors this season to nine appearances and 8 IP between April, July, and August, (1.13 ERA, a 2.86 FIP, three walks, seven Ks, .179/.281/.179 line against), with manager Davey Martinez explaining in mid-July, after they sent Thompson down to Triple-A following a pair of outings earlier in the month, that the club wanted to handle him carefully.

“He’s already been on the IL,” Martinez told reporters. “So with the All-Star break, everything going on, we wanted to send him out, get him built up, get him to throw back-to-back days, because he hasn’t really done that here. It gives us a little time to get him stretched out more. And these other guys, they’ve all been throwing the ball well. So it was tough, it really was.”

In advance of rosters expanding in early September, Martinez was asked if Thompson would be back up for the final month of the season.

“He’s down there [at Triple-A], and he’s just continuing to work on pitches. We want him to throw changeups, we want him to throw a better curveball, more for strikes, so he’s — he’s still a big part of our future. We just want him to go down there and focus on doing these things, not just relying on throwing fastballs, but learning how to pitch, learning how to get out of high-leverage situations using other pitches other than his fastball. So, he’s down there, he’s working, and because we don’t bring him up now, it’s doesn’t mean he’s not — he’ll be in Spring Training, he’ll be one of the guys we’ll be looking at for next year to start with us.”

The Nationals did bring Thompson up a few days later, and he made 15 total appearances out of the bullpen over the final month-plus, posting a 3.78 ERA, a 4.79 FIP, six walks, eight Ks, and a solid .226/.294/.387 line against in 16 ²⁄₃ IP.

Martinez was asked down the stretch how he’d seen Thompson develop over his time in the organization.

“He’s not afraid to attack the strike zone,” the fifth-year skipper said. “He’s done really well. He’s coming in, he’s got a better understanding of how to pitch in, when to use his offspeed stuff, but for me he’s got a little bit of confidence now, and he’s trying to really attack the strike zone, he’s done really well. He’s got a better understanding of how to pitch in, when to use his offspeed stuff, but for me he’s got a little bit of confidence now, and he’s trying to really attack the strike zone, which is really nice.”

Thompson still threw his sinker 72.8% of the time in the majors this season (95.8 MPH average; .233 BAA), while mixing in his slider (23.9%, 84.4 MPH, .067 BAA), and occasionally throwing a four-seamer (1.9%), and changeup (1.4%).

“He’s got great stuff. We knew that,” Martinez said as the season wound down.

“That’s why we traded for him. We thought this guy could really help us, and he’s doing a lot of other things. We talked about maybe going down there [to Triple-A] and get him to throw multiple innings, he’s done that, he’s done it well. Now the big thing for us is to keep him engaged, keep him healthy. The big thing is his health, and keep him, just like [Hunter] Harvey, you know, keep them both healthy, because I think they can both help us here in the future.”

Photo by Scott Taetsch/Getty Images

The manager went on to talk about how working the changeup into his pitch mix could benefit the hard-throwing righty in the future.

“If he can mix in a changeup, he’ll have three really good pitches, because his slider has gotten better, and the changeup will work, especially against left-handed hitting,” Martinez explained.

“So we’ve talked to him, I know [Pitching Coach Jim] Hickey has been on him about using it more and throwing it in games, especially now, just to see what it does. He’s thrown a couple. We’d like to see him throw a few more, but like I said, he’s been so good, just attacking the strike zone with his fastball, and his fastball has been playing really well.

“It’s been all good for him so far, and like I said, we just want him to finish the season up strong and healthy.”