Fitzgerald was injured in the first half of the Cardinals' 14-6 victory over the Detroit Lions on Sunday after taking a hit.
According to Werder, Fitzgerald is believed to have suffered an injury to the medial collateral ligament in his left knee, but the wide receiver thinks he will be able to play through the injury.
"Larry came back and played, so we'll see how sore he is Monday," Cardinals head coach Bruce Arians said after the game
Fitzgerald, 31, has 46 catches and 658 yards and two touchdowns this season for the Cardinals (9-1). With his first catch of the game against the Lions, Fitzgerald became the second fastest wide receiver in NFL history to have 12,000 career receiving yards. Randy Moss was the fastest.
The Cardinals, who have an NFL-best 9-1 record, visit the Seattle Seahawks (6-4) in Week 12.
- Scooby Axson