Gillespie left Wednesday's game against Creighton with 6 minutes, 38 seconds remaining in the first half after landing awkwardly and immediately grabbing at his left leg. He tried to walk it off along the baseline after the play, but he left the bench shortly after and had to be helped to the locker room. Gillespie didn't return, and coach Jay Wright said after the game it was a "serious" injury.
An MRI on Thursday morning confirmed the MCL tear.
"We are all devastated for Collin," Wright said. "He is the heart and soul of our program. We know we can't replace him. We all just want to step up and play so that we can honor him. Collin is as mentally tough and resilient as any player we have had here. I know he will get through this and make it a positive for his career."
Gillespie, a 6-foot-3 senior, was averaging 14.0 points and 4.6 assists this season. He has been the starting point guard for Villanova the past three seasons after playing a key role off the bench on the Wildcats' national championship team in 2018. He was recently named one of the five finalists for the Bob Cousy Award, honoring the nation's best point guard.
Because the NCAA is giving an additional year of eligibility to every winter sport student-athlete, Gillespie is eligible to return to Villanova next season if he chooses.
Villanova went on to beat Creighton 72-60 on Wednesday night. Brandon Slater took Gillespie's spot in the lineup, while Justin Moore and even big man Jeremiah Robinson-Earl took on more of the playmaking duties.
The No. 10 Wildcats clinched the Big East regular-season title with their win over the Bluejays.