In a series of pitching-related roster moves on Thursday, the Nationals placed left-handed reliever Sean Doolittle on the 10-day injured list with a fatigued right knee. The transaction is retroactive to Tuesday.

“His right knee has some inflammation in it,” manager Dave Martinez said. “It’s a testament, I think, that he’s working really hard to get back. … We don’t want him to regress; we want to keep progressing. Him trying to land on that right foot won’t be good.”

Doolittle has struggled this season, with a 15.00 ERA in three innings. He has been candid about his frustration and disappointment.

“I feel terrible,” Doolittle said after allowing back-to-back home runs to the Orioles last weekend. “I’m letting the team down.”

Doolittle went on the IL last Aug. 18 for tendinitis in his right knee. Following his outing on Saturday, he noted that the knee felt "strong" and his arm felt "good." When asked about the possibility of taking some time off, like he did in 2019, he responded, "I hope it doesn't come to that."

“Mechanically, I might not be exactly where I want to be,” he said, “but I feel physically like the ball should be coming out a lot harder than 89, 90 [mph]. It should have some life on it. I should be able to get through an inning. It just hasn’t come together.”

Since players on the IL cannot travel, Doolittle will stay back when the Nationals play in Baltimore this weekend. Martinez expects that Doolittle will spend time at the alternate training site in Fredericksburg, Va., with the medical staff there.

“Hopefully, this is a minor thing and we can get him back here as soon as possible,” Martinez said. “Like I said, we need him.” 

Doolittle and Sam Freeman had been the only two left-handers in the Nationals' bullpen, but Freeman also was placed on the IL on Thursday with a strained left flexor mass. He exited Wednesday’s game against the Mets after feeling a pop in his elbow. Freeman, who underwent Tommy John surgery in 2010, will undergo an MRI on Friday when the team returns to Washington. He has a 0.00 ERA in seven appearances (five innings) this season.

In need of another lefty option, the Nationals selected the contract of Seth Romero, their No. 11 prospect per MLB Pipeline. The 24-year-old has been impressing at the alternate training site, and he is one of five players on the taxi squad for this road trip. Washington drafted Romero with the 25th overall pick in 2017. He spent the 2019 season recovering from Tommy John surgery the previous year. His first outing will be his Major League debut.

That first outing came right away, in the series finale vs. the Mets. Romero struck out his first batter, Billy Hamilton, but struggled from there, allowing four runs -- all of them on Tomás Nido's grand slam in Washington's 8-2 loss.

With Romero the only healthy left-hander in the bullpen, the Nationals could seek to add an arm to bolster their relief corps.

“I know [general manager Mike Rizzo] is looking elsewhere,” Martinez said. “But we’ll see. We’ll see what happens in the next few days.” 

The Nationals also got a veteran arm back in their ‘pen on Thursday, with right-hander Will Harris reinstated from the 10-day IL. Harris, 35, appeared in two games prior to being placed on the IL on July 31 (retroactive to July 29) with a strained right groin. He allowed three runs (one earned) on three hits with two walks and two strikeouts in 1 1/3 innings across those two games.

“It’s good to get Will back,” Martinez said.