"He will be in the hospital for a considerable period of time, presumably weeks", said Jack Sava, trauma director at MedStar Washington Hospital Center, who spoke Friday about the Louisiana Republican who remains in critical condition at the hospital in the District.
Scalise was shot in the hip, and the bullet damaged bone, blood vessels and internal organs.
Nonetheless, Sava said, "We fully expect him to be able to walk" and "hopefully run".
"He underwent another surgery today, but continues to show signs of improvement", it said.
Several other people were also injured in Wednesday's shooting before Scalise's security detail and other police officers gunned down the assailant, who later died.
The man who shot senior Republican congressman Steve Scalise and others at a congressional baseball practice session this week had a list containing the names of three politicians, officials said.
"On behalf of Steve and our children, I want to thank everyone from the bottom of our hearts for the incredible amount of prayers and warm wishes we have received since Wednesday's events", Scalise's wife, Jennifer, said in a statement Friday. Congressional staffer Zack Barth was shot in the left calf.
Scalise was among three people shot by 66-year-old James Hodgkinson on Wednesday.
"My dear friend Steve Scalise took a bullet for all of us", Trump said.
Hodgkinson posted content favorable to Democratic presidential candidate Bernie Sanders on his social media accounts and signed a Change.org petition for the removal of Trump and Vice President Mike Pence. Doctors said his prognosis was positive on Friday. The offices of both senators - Dick Durbin and Tammy Duckworth - turned over the emails to Capitol Police and declined to offer specifics about their content.
Lobbyist Matt Mika was shot multiple times and critically injured and remained hospitalized.
Sava also said that Crystal Griner, one of the U.S. Capitol Police officers credited with saving Scalise and others at the field, sustained a gunshot wound to her ankle.
According to the American Hospital Association, "serious" and "critical" condition is among the two most grave designations that medical officials use to describe a patient's general condition, though "serious" is a less urgent designation than "critical".