The lone undefeated team in the NFC, the San Francisco 49ers (8-0) held off the Arizona Cardinals (3-5-1), 28-25, on Thursday night at State Farm Stadium in Glendale.

However, there was some bad news for San Francisco: Linebacker Kwon Alexander, a former LSU Tiger, suffered a torn pectoral muscle and will miss the remainder of the season.

Citing Ian Rapoport, the NFL shared the news on Twitter:

An Oxford, Alabama product, Alexander was a four-star recruit in the 2012 cycle. Leaving Baton Rouge after his junior year, he accumulated 167 tackles (15 TFL) and one-and-a-half sacks during his time playing for Les Miles.

Selected in the fourth round (No. 124 overall) by the Tampa Bay Buccaneers in the 2015 NFL Draft, Alexander agreed to a four-year/$54M deal – including $27M guaranteed – with the 49ers in March.

Despite being limited to 12 games, he was named to the NFC Pro Bowl team in 2017 for his 97-tackle, three-interception performance.

Hoping to remain unbeaten, the 49ers will next be in action on Monday, November 11 vs. the Seattle Seahawks (6-2) at Levi’s Stadium in Santa Clara.

Idle on Saturday, Alexander’s alma mater will face No. 2 Alabama on November 9 at 3:30PM ET as part of the SEC on CBS.