USC linebacker Porter Gustin's career with the Trojans is over. The school announced Sunday that the 6-foot-5, 255-pound senior suffered an ankle injury late in the fourth quarter on the final defensive drive of Saturday's 31-20 win over Colorado.

"That will take him out for the rest of the season," said USC coach Clay Helton said Sunday night, according to 247Sports

Gustin was one of the Trojans' top players, and an integral part of its defense. He tallied 10 tackles for loss and seven sacks prior to the injury -- tops on the team in both categories. His 28 tackles are third-most on the Trojans. He earned honorable mention honors from the Pac-12 following his sophomore season in 2016, when he started every game at outside linebacker. His junior season was de-railed by multiple injuries, including a broken toe and a torn bicep.

"It's extremely hard because he's put so much into it, has done so much for our team," Helton said, according to the Los Angeles Times. "But now it's about him going through this surgery, him getting well and us focusing on getting him well. It's going to be a three-to-four-month process to get him back where he can show exactly what we all know, that he's a NFL football player, to NFL general managers and scouts."

With Gustin out, junior Christian Rector could see more time. Rector filled in admirably when Gustin was out of the lineup last year, notching 35 tackles, 11 for loss and 7.5 sacks.

USC will head to Utah Saturday night to take on the Utes in a critical Pac-12 South showdown.