According to the Spartans' medical staff, a small piece of cartilage got loose in Valentine's knee and the doctors cleaned it up in the procedure.
The senior reportedly suffered the injury during Sunday's practice but he isn't sure exactly when the injury occurred. Head coach Tom Izzo guessed that it happened while going in for a layup, but wasn't certain when found out the news Sunday night.
Valentine leads the team with 18.5 points, 8.3 rebounds, and 7.1 assists per game. He has already recorded his first two career triple-doubles this season, and he will be watching from the sidelines as his Spartans start Big Ten play on December 29th against Iowa.
If the Player of the Year candidate misses the four games he is expected to miss, Michigan State will be going up against Oakland, Iowa, Minnesota, and Illinois without him.
MSU remains one of just six undefeated teams left in the country and will put that on the line on Tuesday when they battle the Grizzlies at The Palace. The Spartans haven't just been about Valentine this season, and they look to prove their depth in the coming weeks without their star.