In the scene where Carosi finds out that the team's tallest player is injured, you can see a large bandage behind Screech's right elbow when he approaches Carosi. No explanation is given in the episode on how it got there.
Mr. Carosi: Look, I - (double take) you sure are tall, son. Have a roll.
Gary: Thanks. I love rolls.
Mr. Carosi: Have a dozen.