Quinn has missed four of the Rams’ last five games. He will undergo back surgery after recording five sacks in eight games this season. Quinn, a former first-round pick, has 50 sacks in his career and is signed through 2019.
McDonald, a 2013 third-round pick, has started 11 games for St. Louis in 2015, recording 63 tackles, a sack and a forced fumble. McDonald will undergo shoulder surgery and is signed through next season.
The 4–8 Rams will host the 4–8 Lions in Week 14.