The 24-year-old was forced to play against the Pittsburgh Steelers despite having an ankle injury as primary back Lamar Miller left the game with a concussion but Thomas put in a stellar performance rushing for 105 yards a touchdown.
"There is a certain amount of mental toughness that plays a part in it," Sherman told South Florida Sun-Sentinel. "He wasn't 100 percent but he played as if he was.
"There's one thing to play with some pain and another things to play well with some pain, and he certainly played well."
The Dolphins are 7-6 in their season and face the New England Patriots in week 15.