He was shot in the hip but the bullet tore through his pelvis and injured internal organs.
Trump also adds, as he's said previously, that Scalise is "having a hard time, far worse than anybody thought" following the shooting Wednesday.
Scalise, 51, the No. 3 House Republican leader, was first elected in 2008.
The Republican lawmaker was treated at a Washington hospital Wednesday after a single rifle shot struck his hip during a shooting attack at a GOP congressional baseball practice in suburban Virginia. Scalise was honored Thursday night during the annual congressional baseball game.
Republicans and Democrats have shown they can engage in a spirited rivalry without rancor - at least on the ballfield.
House Republicans met privately earlier to discuss the shootings, pray and sign oversized cards for the wounded. Democratic Rep. Gabby Giffords of Arizona was hit in the head and grievously injured while meeting with constituents at a supermarket parking lot in 2011.
Democrats won in an 11-2 blowout.
If Scalise did not suffer nerve damage and his recovery continues without any complications, "it is possible that within three months or so, he can.be back on his feet", said Dr. Alex Jahangir, an orthopedic trauma surgeon at Vanderbilt University Medical Center, who was not involved in Scalise's care.
David Bailey walked to the pitcher's mound on crutches and former New York Yankees manager Joe Torre handed him the game ball.
The president paid a visit to Scalise on Wednesday night, meeting with Scalise's family and sitting by the congressman's bedside. He sustained a relatively minor injury Wednesday morning as he and other officers engaged with a gunman who shot up a practice of the GOP baseball team. He remains in critical condition.
"I could spend hours on this program giving example after example of these left-wing celebrities, these Trump detractors glorifying violence against the President of the United States, and virtually no one on the left has denounced this vile behavior", he said.
Trump wasn't able to attend the event in person due to security protocols.
Pence tweeted shortly after leaving the MedStar Washington Hospital Center on Thursday morning that he and his wife, Karen, had thanked doctors and hospital staff.
Hunt says it's not uncommon for gunshot victims to have multiple surgeries.
Trump ends his remarks with, "Ladies and gentlemen, let's play ball".
President Trump on Thursday said the shooting of Rep. Steve Scalise had a silver lining because the attack on the conservative Republican by a leftwing nutjob will help unify the country.
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 others wounded were a police officer, a congressional aide and a lobbyist.
The shooter was identified as James T. Hodgkinson, a 66-year-old home inspector from IL who had several minor run-ins with the law in recent years and belonged to a Facebook group called "Terminate the Republican Party".
She says that everyone should examine their own conscience. The man calmly asked which party's lawmakers were practicing and Duncan told him they were the Republicans. The shooter later died from his injuries.
The driver was arrested for failure to obey an order and assault with a risky weapon. The gunman had apparently been in the Alexandria area since March and was living out of his van near the baseball field, Slater said. Investigators are still studying James T. Hodgkinson's social media profile and activities leading up to the attack.
Democrat Cedric Richmond, a fellow Louisiana congressman, said as many others did that Scalise is a fighter. Capitol Police said they had "no evidence to suggest that the purchases were not lawful". The official was not authorized to speak publicly about the investigation and did so only on condition of anonymity.