San Francisco 49ers linebacker Kwon Alexander reportedly tore his pectoral muscle on Thursday night against the Arizona Cardinals and will miss the remainder of the season.
Alexander exited the game and did not return, and ESPN's Adam Schefter tweeted Friday morning that an MRI revealed that the injury would be season-ending.
The injury is a big blow to the 49ers, as Alexander was second on the team in total tackles. Reserve linebacker Azeez Al-Shaair filled in for Alexander on Thursday night, and if Alexander goes on injured reserve, the 49ers would have an open roster spot to bring in a new backup.