According to Joe Vardon and Sam Amick of The Athletic, "Leonard's knee issue stems from overcompensating for his injured right quad suffered last season."
Vardon added that his quad is now "fine," but his knee has caused the forward to be "laboring at times."
Leonard's quad injury was a major story in the NBA last season as the superstar was held to just nine games. Disagreements between him and the San Antonio Spurs doctors led to a rift within the organization and eventually his trade to Toronto.
His uncle, Dennis Robertson, explained the problems with the Spurs last season.
"I think it just became a lack of trust," Robertson recently told Chris Haynes of Yahoo Sports. "They didn't believe Kawhi couldn't play and that caused a lack of trust in us and then us not believing in them. Any time a player says he's not capable of playing, you should believe him."
The Raptors were much more patient with Leonard this season, sitting him out for 22 regular-season games to keep him fresh for the playoffs. However, it now appears last year's problems have carried over in a different way.
Leonard hasn't missed a game this postseason, but teammate Danny Green admitted before the NBA Finals that Leonard is dealing with a knee injury, via Josh Lewenberg of TSN Sports.
Considering he is averaging 30.9 points and 9.1 rebounds per game during the playoffs even with the injury, it's scary to think of what he would be doing at full strength.