Cooper Kupp is out for the season. Wide Receiver Cooper Kupp #18 of the Los Angeles Rams runs after a catch in the second half against the Seattle Seahawks at CenturyLink Field on October 7, 2018 in Seattle, Washington. Stephen Brashear/Getty Images

As the Los Angeles Rams gear up for one of their biggest games of the season, the NFC’s top team will be without one of their most valuable offensive weapons.

Ahead of a Monday night matchup against the Kansas City Chiefs, the Rams learned that wide receiver Cooper Kupp will miss the rest of the season and would likely have surgery this week to repair a torn anterior cruciate ligament (ACL), according to

Kupp’s injury came Sunday in the fourth quarter against the Seattle Seahawks. In a non-contact play, the 25-year-old ran a route and then fell to the turf and clutched his knee.

The second-year star has been an important weapon in the Rams' highly efficient passing attack. Kupp caught 40 passes for 566 yards and a team-leading six receiving touchdowns.

It is unclear when Kupp will return, as recovery times vary greatly for ACL injuries. Standard ACL rehab can take up to nine months to complete.

New England Patriots wide receiver Julian Edelman tore his ACL in August 2017 and returned to action roughly a year later. Former Minnesota Vikings star Adrian Peterson tore his ACL in December 2011 and then returned to lead the league in rushing yards in an MVP season.

Josh Reynolds is expected to fill in for Kupp in a role meant to ease pressure off of the Rams’ duo of Brandin Cooks and Robert Woods. The 23-year-old has seven receptions for 98 yards on the season.

The Rams appear poised to win the NFC West and earn one of the top two seeds.

With their high-powered offense and talented defense, the Rams are listed as the favorites to win the Super Bowl this year, according to OddsShark. However, at +325 odds, they are not overwhelming favorites over the +400 New Orleans Saints and +500 Chiefs.