An MCL sparain in his left knee that may require surgery, according to coaches.
The MCL is a ligament that helps stabilize the knee joint. A Grade 3 tear, according to the report, could cause a player significant pain, swelling and instability. Surgery is not necessarily required.
Cutler's injury certainly hasn't softened the blow of Sunday's loss.
Even pros are weighing in on the game, including Deion Sanders, who Tweeted, "I better see dr andrews operate live on Cutler and Collins tonight after the game on nfl network. Truth."
Maurice Jones-Drew Tweeted, "All I'm saying is that he can finish the game on a hurt knee... I played the whole season on one."
Some are sticking in Cutler's corner, though, including one Twitter group, #isupportjaycutler.
Says @CHItownGEEK, "Jay Cutler is a lot of things, tough is one of em. how can you say a guy who took 57 sacks is a wuss."