Jack Sinclair didn’t open the year on the Nationals’ radar as a late-game answer. He wasn’t in big league camp, spent the spring on the minor league side and spent most of the season back in Rochester. But by the end of September, the 27-year-old right-hander had worked his way into Washington’s bullpen mix and earned trust in some of the biggest spots available.
Manager Blake Butera said Sinclair’s late-season rise was not something the club expected when the year began.
“I told Jack … that I'd be lying if we thought that he was going to be throwing leverage innings for us at the end of the year here when we're pitching pretty well out of the bullpen, and that's a testament to him,” said manager Blake Butera. “He put the work in.”
Sinclair made his Major League debut on Sept. 4 and went on to appear in 11 games for the Nationals. He finished 1-0 with a 2.45 ERA and one save over 11 innings, giving Washington a steady arm during a stretch when the bullpen was dealing with record-high blown saves.
The numbers backed up the eye test. Right-handed hitters barely touched him, batting just .048 against him. Butera said the club leaned on him in key moments, especially in the eighth inning, where Sinclair posted a 2.45 ERA and held opponents to a .160 average.
“We used him in some big spots,” said Butera. “I think that you just get a good feeling when he takes the ball. We’ve asked a lot from him.”
That kind of reliability mattered for a relief group that needed answers late in the season. Butera praised the way Sinclair handled the pressure, pointing to his consistent demeanor every time he took the mound.
“He's just the same guy every time, and he's not afraid of the moment,” said Butera. “I think that there's a lot to be said for that when you pitch in the back of a bullpen.”
Before his call-up, Sinclair had already put in a heavy workload at Triple-A Rochester. In 52 appearances with the Red Wings, he went 6-2 with one save and a 4.03 ERA. He struck out 74 batters, including 72 as a reliever, which tied for third-most among Nationals minor league pitchers, and he allowed only four home runs.
The season ended up being his fifth full year in pro ball and his heaviest relief load since the Nationals drafted him in the 16th round in 2021 out of the University of Central Florida. He logged 71 1/3 relief innings, his highest total since turning pro.
“It’s been pretty cool; it's been a lot of throwing,” Sinclair said. “But overall, I felt the best I’ve felt in a season, so that part's good. It's been a lot of fun, and I’m excited for the offseason, going into next year and building off of this year, and hopefully making improvements.”
When he got to the majors, Sinclair leaned heavily on his sweeper and four-seamer, while also mixing in a sinker, slider and changeup. Opponents managed just one hit in 14 at-bats against the sweeper and went 3-for-14 against the four-seamer, which averaged 96.9 mph. The Nationals want him to keep pushing that velocity upward next season.
“[I want to work on] my body more, strength and gaining weight,” said Sinclair. “For me, it's hard to keep my weight on during the season.
At the start of the year, I started where I wanted to, and then I’ve fluctuated the whole year. But getting that foundation back and getting stronger, maybe that helps more velocity.
And then I want to improve my stuff, the sweeper, fine-tuning everything and getting it where I want for next year.”
Sinclair said he’s willing to pitch whenever the team needs him, and Washington used him in four of its final five games. The Nationals are hoping that becomes a familiar sight in 2027.
“It’s definitely good to have some success here and know that I can compete at this level and get really good hitters out,” said Sinclair. “That part's good for my confidence, knowing that I can do that. I just want them to be able to call my name and they can rely on me to do the job they want.”
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