Bennie Boatwright will be sidelined for the remainder of USC's season because of a knee injury.
"It hurts a lot," senior point guard Jordan McLaughlin said after practice Friday. "He's a big part of our team."
USC (18-9 overall, 9-5 in Pac-12 Conference play) is tied for second place with UCLA (18-8, 9-5) as the Trojans prepare to host Oregon State (13-12, 5-8) on Saturday at the Galen Center.
With four games remaining before the conference tournament, coach Andy Enfield said it would be crucial for USC to win its games at home.
But it becomes more difficult without Boatwright, who averaged 13.6 points and 6.4 rebounds per game. "It's devastating," Enfield said. "It's really unfortunate and heartbreaking."
Boatwright injured his left patella Thursday while playing defense during the second half of a victory over Oregon.
He is not expected to undergo surgery, but will require 8-12 weeks for recovery.
Boatwright, a junior forward, has dealt with nagging injuries the last two seasons. He was sidelined for two nonconference games in December and then again against Stanford and California last month because of a callus on his foot that became infected.
He also was sidelined for 17 games last season as he recovered from offseason labrum surgery, followed by a sprained knee.
Junior forward Chimezie Metu said Boatwright would be missed on both ends of the floor.
"He gave us an extra body down there to kind of defend guys," Metu said. "On offense he spaces the floor for us, knocks down open shots."
Sophomore forward Nick Rakocevic was inserted into the starting lineup for six games this season when Boatwright was sidelined or slowed because of the foot injury.
Rakocevic, averaging 7.8 points and 5.3 rebounds, took over as a starter again when Boatwright was sidelined against Stanford and has maintained the role for the last six games.
"We have experience playing without key players," Enfield said. "But we have to play well together."
VS. OREGON STATE
Where: Galen Center.
On the air: TV: FS1; Radio: 710.
Update: Metu made a last-second layup to stop a three-game losing streak and lift USC to a 72-70 victory over Oregon on Thursday. Jonah Mathews made his first start since Jan. 7 and scored a team-high 20 points. After sweeping the Washington schools at home, Oregon State is coming off a 75-68 loss at UCLA.