Gilbert, who signed in late September after going to training camp on a professional tryout, underwent sports hernia surgery in Philadelphia on Thursday.
Gilbert had played in all of Florida's first 73 games, totaling three goals, 25 assists and a minus-5 rating. His average ice time of 21:20 is second on the Panthers behind defense partner Brian Campbell, who is averaging 27:17.
"He's been dealing with it for a while and playing through it, having to take therapy and medicine," Panthers interim head coach Peter Horachek said after morning skate in preparation for a game against the Carolina Hurricanes on Thursday. "It was to a point where something needed to done."
Though Gilbert leaves the Florida lineup, the Panthers will welcome the return of defenseman Erik Gudbranson after a nine-game absence because of a knee injury.
Gudbranson will be playing for the first time since being hurt March 9 in the third period of a 5-2 loss against the Boston Bruins. Gudbranson, who earlier missed five games after undergoing orbital bone surgery, said he feared the injury, as the result of a collision with Boston forward Brad Marchand, would be much more severe.
"I watched the video afterwards with the doctor," Gudbranson said. "He was surprised that he didn't have to rebuild my knee. It was a best-case scenario that came out of that fall. I'm really lucky."
Coming off a 3-2 shootout victory against the Ottawa Senators on Tuesday, the Panthers will try to win consecutive games for the first time since Jan. 20-21.
The Hurricanes haven't given up hope for a Stanley Cup Playoff spot, but their chances are slim. Carolina has 71 points, nine out of the last playoff spot in the Eastern Conference, with 10 games left.
"We know where we're at," Hurricanes captain Eric Staal said. "It's going to take a lot of different scenarios and us winning probably all of them. We need to start with one [Thursday], take it a day at a time as the old cliché goes, and be ready to come out with a good effort tonight.”
The Hurricanes will be looking to bounce back from a 5-4 home loss against the New York Islanders, a game where they trailed 4-0 in the first period before their comeback attempt fell short.
"You've got to approach every game with respect to your opponents," Hurricanes coach Kirk Muller said. "Everyone is playing for different reasons. [We're facing] another team here with a lot of youth in the lineup, guys wanting to play for jobs. So our focus should be, despite whether we're playing a first-place team, last, middle, whatever, we've got to come out consistently better in the first, and we've got to come out with some structure to our game and some bite to our game. Our second and third periods have been very, very strong. It's the first periods that have been hurting us."
Veteran forward Radek Dvorak will be back in the Hurricanes lineup against Florida, a team with which he had two different stints. Dvorak's 613 games with the Panthers ranks second in franchise history behind Stephen Weiss' 654.
Goalie Anton Khudobin, who came in after Cam Ward gave up three goals on nine shots in the first six minutes against the Islanders on Tuesday, will start for Carolina. He'll be facing Roberto Luongo, who will start for the 10th time in 12 games since his return to Florida.
Here are the projected lineups for the Hurricanes and Panthers on Thursday at BB&T Center:
Injured: Joni Pitkanen (heel)