Strome missed the Rangers' 4-1 loss in Game 4 on Tuesday with a lower-body injury after leaving in the second period of Game 3 on Sunday. Chytil sustained an upper-body injury in the second period Tuesday.
The best-of-7 series is tied 2-2 after the Lightning won the past two games at home.
Strome, who has nine points (two goals, seven assists) in 17 games in the Stanley Cup Playoffs, was injured after being shoved from behind by Tampa Bay forward Ondrej Palat early in the second period of New York's 3-2 loss in Game 3. After heading to the locker room, the center returned for one shift later in the period but left before intermission and did not return for the third.
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Gallant had been hopeful Strome would play Tuesday and said he was "real close," but the decision was made to hold him out after he participated in warmups.
"I expected him last night and I wasn't lying," Gallant said Wednesday. "I expected him to play and there are game-time decisions and you've got to make the right ones and they're tough calls for everybody, but I felt we made the right one last night."
Chytil did not play after being hit into the boards and glass by Lightning defenseman Victor Hedman with 6:27 remaining in the second period Tuesday. The center has nine points (seven goals, two assists) in 18 games in the playoffs, including two goals in a 6-2 victory in Game 1 against Tampa Bay. He has been a key part of New York's effective third line with Alexis Lafreniere and Kaapo Kakko.
Had Chytil and Strome been unable to play Thursday, the Rangers would have been without two of their top three centers. With Strome out Tuesday, Andrew Copp moved from wing to center on the second line, and Barclay Goodrow moved up from the fourth line to play wing on the second line.
Kevin Rooney dressed for the first time in the series and took Goodrow's spot as the fourth-line center.
"There was the possibility that [Strome] wasn't going to be able to go and I knew I was going to go in the middle," Copp said. "So I would say I was prepared for it. At this time of the year, guys are going to go down and that's part of what I feel like I'm good at, is my versatility."