Cousins's right leg buckled as he was dropping back to pass and he was sacked on the play. He hopped to the sideline on his left leg and was evaluated in the medical tent before being carted to the locker room.
Vikings head coach Kevin O'Connell told reporters after the team's 24-10 win over the Green Bay Packers that he feared it was an Achilles injury. ESPN reported, citing a source, that Cousins had a torn Achilles.
He will undergo an MRI examination to determine the extent of the injury but the expectation is that his season is over, NFL Network reported.
Cousins was 23-of-31 passing for 274 yards with two touchdowns at the time of the injury. The veteran signal-caller has never missed a game with an injury and will be a free agent after this season.
While likely the worst injury to a quarterback in the early games on Sunday, Cousins was far from alone.
Rams quarterback Matthew Stafford (35)left with a right thumb injury in Los Angeles' blowout road loss to the Dallas Cowboys.
Pittsburgh signal-caller Kenny Pickett (25) took a shot to the ribs from a Jaguars defensive lineman just before half-time and was later ruled out of the game.
New York Giants Tyrod Taylor (34), starting in his third game in the place of the injured Daniel Jones, left in the first half of his team's overtime loss with a rib injury also caused by a hard hit.
