The Stars announced that Seguin has a lower-body injury. Coach Lindy Ruff told reporters on Saturday that the 23-year-old center has a knee injury and could miss two to four weeks, though sources told ESPN's Pierre LeBrun that timeline could stretch to three to six weeks.
Seguin was helped off the ice Friday after the hit in the third period by Florida defenseman Dmitry Kulikov, who was ejected. Kulikov is likely to be suspended.
Kulikov went low and hit Seguin on his right knee just after the Dallas forward entered his offensive zone and made a pass. Dallas defenseman Alex Goligoski and Kulikov had to be separated by a referee after the play.
"It's a play that I don't like," Ruff told reporters Saturday in Denver, hours before the Stars lost to Colorado 4-1 on the second night of a back-to-back. "It's a dirty, low play that I don't like. The league doesn't like it, and I want to see the league deal with it."
Seguin started the day third in the NHL with 59 points and tied for fourth with 29 goals.
"He's released the puck, and (Kulikov) comes across and takes his knee out," teammate Vernon Fiddler said. "It's a gutless play on his part, and we'll have to deal with that at a later time."
The Stars also lost two other forwards against the Panthers. Ales Hemsky left with a lower body injury in the first period, and Patrick Eaves went to the locker room 51 seconds after Seguin when teammate John Klingberg's wrist shot hit Eaves in the head.
All three players missed the trip to Colorado, and the Stars recalled forwards Brett Ritchie and Travis Morin from the Texas Stars of the AHL to fill the void. Seguin and Eaves were placed on injured reserve.
Ruff said X-rays showed no fractures for Eaves, who has a history of concussions and is being evaluated for one. Hemsky could return next week.
The Stars are chasing the final playoff spot in the Western Conference, and the Panthers are doing the same in the East. They play their only other regular-season game March 5 in South Florida.
Information from The Associated Press was used in this report.