The junior, who started every game this season, tore the ACL and medial meniscus in his left knee on Friday, the team said Sunday. He is scheduled to undergo surgery this Friday.
Polley averaged 9.5 points and 3.2 rebounds this season. He scored a game-high 19 points and pulled down a career-high 11 rebounds Wednesday while playing 35 minutes in a win over Tulane.
UConn lost to No. 23 Wichita State 89-86 in double-overtime on Sunday. Polley was introduced to the crowd after the starting lineups were announced and received a raucous ovation.
"It's hard, but I'm trying to stay positive," Polley said after the game. "I've got people around me, great teammates and coaches supporting me and having my back, so it helps."
Freshman James Bouknight replaced Polley in the starting lineup Sunday and scored 16 points.