Tiger Woods lost the Masters by three shots and it might have been because his knee was hurting.
Just 48 hours after playing in the Masters, Woods underwent arthroscopic knee surgery on Tuesday.
In 1994, Woods had surgery on the same knee to remove a benign tumor.
Tiger is expected to be out the next four weeks while he recovers. That means he will miss the Players Championship in May.
However, Woods expects to be ready for the US Open Fathers Day weekend.
Tiger said he decided before the Masters to play despite the pain. Woods is confident he can come back since hes gone through the rehab process before.