Instead of wearing hats representing their home teams, as is the normal tradition, players on both teams wore Louisiana State University hats in honor of Scalise, a Louisiana Republican, for part of the game.
"The congressman's status remains critical", Dr Jack Sava, the director of trauma at the MedStar Washington Hospital Center, told reporters.
Although Scalise was able to talk while lying injured on the ball field, he had gone into shock by the time he was transported by helicopter to the hospital and arrived "in critical condition with an imminent risk of death", Sava said.
Colleagues who visited Scalise, including House Speaker Paul Ryan, sounded generally upbeat, but spoke more in terms of hopes than the confident predictions of the immediate aftermath a day earlier.
Scalise, 51, and four others were wounded when an IL man opened fire Wednesday morning on the team practice in Alexandria.
Game organizers say more than 20,000 tickets have been sold, and more than $1 million has been raised for Congressional Sports for Charity.
Law enforcement officials have said they found a list of Republican lawmakers' names on the body of James Hodgkinson, who apparently had been in the Washington area for several months stalking his targets.
"My dear friend Steve Scalise took a bullet for all of us and because of him - and all the tremendous pain and suffering he has endured, he is having a hard time, far worse than anyone thought - our country will perhaps become closer, more unified, so important", Trump said.
Describing themselves as "much tougher" and "resilient" after the attack that united them in the way only survivors of mass shootings know too well, members separated themselves from yesterday's tragedies and zoned in on the game.
He was one of five people injured from gunshots during the shooting but the only congressman who was hit. His physicians have indicated extensive hospital treatment will be necessary, followed by a period of rehabilitation.
Of immediate concern to doctors when Scalise arrived was hemorrhaging.
The bullet entered Scalise's left hip and tore across his pelvis, cracking bones and injuring organs and blood vessels.
The majority whip keeps track of House members and tries to sway them to vote a certain way.
With summer congressional recesses approaching, the House of Representatives is expected to be in session for only several weeks from now until the end of September, which closes out the USA government's 2017 fiscal year.
House Minority Leader Nancy Pelosi, D-Calif., recounted candidate Trump's comments prodding supporters to pummel demonstrators at rallies and said Republicans were being "sanctimonious".
Numerous players in the congressional game Thursday night are wearing Louisiana State University hats in honor of Scalise, a graduate of the school, as they assemble at Nationals Park in Washington.
The congressional game, which dates to 1909 and is a summertime tradition on Capitol Hill, is a rare example of bipartisanship in an increasingly polarized Washington.