PHILADELPHIA -- The Nationals' bullpen took another hit on Tuesday when the club placed right-hander Kyle Finnegan on the 10-day injured list due to a left hamstring strain.

Though Finnegan tossed a quick scoreless inning in his last appearance on Sunday against the Mets, he tweaked his hamstring on the final offering of his five-pitch outing. While it initially felt like a cramp, manager Dave Martinez said that Finnegan felt it "grab" as he got back to the dugout.

"Hopefully we get him back fairly soon," Martinez said. "He's going to take a few days off to get treatment, then he'll get right back in it and start going again, and we'll see where we're at."

The bullpen has played a key role for a Nationals team that entered Tuesday having won seven of its last eight games. Washington's relief corps had allowed only one run over 17 1/3 innings during that eight-game stretch, good for a 0.52 ERA.

Finnegan appeared in four of those eight games, earning a win and a pair of holds while taking on a larger role in the absence of Daniel Hudson, who last pitched on June 9 and remains on the 10-day IL with right elbow inflammation.

Hudson played catch in the outfield at Citizens Bank Park prior to Tuesday's series opener -- an "encouraging sign," per Martinez -- but he's not yet ready to rejoin the bullpen. That all comes after Will Harris underwent surgery on June 4 to alleviate thoracic outlet syndrome, a procedure that could sideline him for the remainder of the 2021 season.

Harris' absence may open up opportunities for left-hander Sam Clay or righty Austin Voth, who just returned Saturday following a nearly two-week absence after he was hit in the face by a pitch on June 6. Voth tossed a scoreless inning against the Mets in his return, lowering his season ERA to 2.64.

That said, Voth has been used primarily in low-leverage spots this season. He's entered only five of his 20 appearances with the Nats holding a lead -- and none of those margins were smaller than three runs.

"Voth had been throwing the ball well before his injury. He came back and threw the ball well the other day, so I'm looking at him right now," Martinez said. "If there's a group of lefties where we feel Clay can get some big outs in a moment like that, then it'll be Clay. There are some spots where I like [Wander] Suero in a big moment, as well. So we have options, which is nice."

That could lead to Martinez opting to play the matchups later in games, as opposed to having set plans for the seventh, eighth and ninth innings, though that will likely be determined on a game-by-game basis for the time being.

"We'll do a little bit of both," Martinez said. "We still have [Tanner] Rainey, we still have [Brad] Hand for high-leverage guys, so we'll see where we're at in the lineup and we'll go from there."