Thomas left the ice with 2:59 remaining in the third period and the score tied 2-2. He was replaced by Jacob Markstrom, who was beaten twice in the shootout as the Blackhawks won 3-2.
Thomas went down to make a save and lay on his stomach in obvious discomfort. After the next whistle, he skated to the Florida bench, moved his leg to test it and showed obvious pain, at which time Markstrom replaced him.
Thomas was making his third start after missing four games with a groin injury he sustained during a 2-1 loss against the Philadelphia Flyers on Oct. 8. Florida coach Kevin Dineen said after the game he had no update on Thomas' condition but that the injury Thomas sustained on Tuesday was not the same as the one he suffered in Philadelphia.
Dineen said the Panthers were calling their American Hockey League team in San Antonio. Florida sent veteran Scott Clemmensen to San Antonio when Thomas returned to the lineup last week.