Intrameniscal degenerative changes, presumably due to mild repetitive trauma, have been shown in many college and professional athletes, but it is uncertain over what period of time they can develop or significantly progress. To ascertain this period, the authors used magnetic resonance (MR) imaging to examine one knee in each of 20 players in the starting lineup of a major college football team before and after the season. Only asymptomatic knees (right, n = 10; left, n = 10) were examined; the images were reviewed blindly by one experienced observer without reference to the other examination. A significant progression existed in the grade of signal intensity shown in the menisci over the course of the season (P less than .001). Although this is a small study covering only 1 year, these preliminary results suggest that significant degeneration can occur in the menisci of asymptomatic players over a single season.