Before the Phillies celebrated their biggest comeback victory in 11 years, they lost two of their most dangerous hitters.

Bryce Harper exited in the third inning of the finale of Thursday’s doubleheader -- a rousing 11-8 victory over the Washington Nationals on Brad Miller’s eighth-inning grand slam -- because his back stiffened up between games. Three innings later, Rhys Hoskins left after tweaking his left groin while trying to make a diving stop earlier in the game.

Manager Joe Girardi characterized both players as “day to day,” although Harper said he expects to be ready to play Friday night in Pittsburgh.

» READ MORE: Brad Miller’s grand slam gives Phillies an 11-8 win, doubleheader split entering trade deadline

“I think [bench coach Rob Thomson] saw me kind of hobbling a little bit, so he came over to me and said, ‘Hey, we’re just going to get you out of this one and get you ready for tomorrow,’” Harper said. “I thought to myself, miss half a game to not miss two. I’ll be in there [Friday].”

Harper’s back has been an issue since the second half of last season when he played through a strained muscle. He did physical therapy in the winter to strengthen his back, which flared a few times earlier in the season.

It appeared that Harper grimaced after booting Andrew Stevenson’s single to right field in the third inning. Hoskins was injured on the same play. He dove to try to snare the ball and came up stretching his groin.

“They’re day to day,” Girardi said. “I don’t know what that means for [Friday].”

Miller, who replaced Harper in right field, singled to start the Phillies’ game-tying three-run rally in the seventh inning before belting the grand slam in the eighth. According to the Elias Sports Bureau, it was the first time the Phillies won after trailing by seven or more runs since Aug. 12, 2010, when they rallied from 9-2 for a 10-9 win over the Los Angeles Dodgers.

» READ MORE: Phillies' Zach Eflin: ‘I don’t know if there’s a timetable’ for return from knee injury

Wanted: Pitchers

Less than 24 hours before the trade deadline, the Phillies were said to still be hunting for help for the rotation and the bullpen. A few names came flying off the board, as the Cubs traded reliever Ryan Tepera to the White Sox and the Nationals sent closer Brad Hand to the Blue Jays. The Dodgers acquired starter Danny Duffy from the Royals.

And what if Phillies president of baseball operations Dave Dombrowski and general manager Sam Fuld strike out in their pitching pursuit?

“Raul Ibanez, one of my mentors in the game and one of my favorite players, has told me over the years: ‘Our contract says player,’” Miller said, referring to the former Phillies outfielder. “I love thinking about the moves and all that stuff, but at the end of the day, I always go back to that. It’s a great piece of advice for us because we do care but they’ll take care of it. They’ll do their thing. Our job is to win ballgames and to perform and to play regardless of who we have.”

Knapp to paternity list

The removal of catching prospect Rafael Marchan from the lineup Wednesday night at double-A Reading fueled speculation that he had been traded. Not so. Marchan got called up to replace backup catcher Andrew Knapp, who went on the paternity list for the birth of his first child, and caught spot-starting lefty Cristopher Sánchez in the second game of the doubleheader.

Marchan’s name has arisen in trade talks over the last few weeks. Although the Phillies are bullish about the 22-year-old’s potential, especially his defense, they may be inclined to move him because J.T. Realmuto is signed through 2025 and Knapp is under control through next season.

» READ MORE: Photos from the Phillies' Game 1 loss to the Nationals

Nats’ COVID update

The Nationals had another staff member test positive for COVID-19, according to manager Dave Martinez, bringing the total to 13 infected members of their traveling party, including four players. Shortstop Trea Turner, catcher Alex Avila, and relievers Daniel Hudson and Austin Voth were placed on the injured list for undisclosed reasons.

MLB postponed Wednesday night’s game to allow for additional testing and contact tracing of Nationals personnel. Martinez said all but one of the people who tested positive has been vaccinated.

Martinez’s staff was impacted by the virus, with the Nationals using a fill-in pitching coach, bullpen coach, assistant hitting coach, first-base coach, and third-base coach. Martinez said he planned to serve as his own bench coach, with assistance from injured slugger Kyle Schwarber.

Extra bases

Andrew McCutchen’s homer in the second game marked his 20th of the season. McCutchen, Nelson Cruz, and Kyle Seager are the only active players with at least nine 20-homer seasons since 2011. ... Nationals star Juan Soto has reached base in 25 consecutive games at Citizens Bank Park, the third-longest streak by an opposing player behind Albert Pujols and Chipper Jones (26 games apiece). ... Vince Velasquez (3-5, 5.54 ERA) is scheduled to start Friday night in Pittsburgh. Aaron Nola (7-6, 4.37) and Spencer Howard (0-2, 5.72) are lined up Saturday and Sunday, respectively.