Minnesota Vikings defensive end Jared Allen was fined $21,000 for his blindside hit of Bears guard Lance Louis, according to a league source.
Louis tore his left ACL, and he was placed on injured reserve Monday. The Bears on Tuesday signed former Pro Bowl center Andre Gurode for depth.
On the opening drive of the third quarter of Sunday's 28-10 Bears victory, quarterback Jay Cutler was off mark on a pass to open receiver Brandon Marshall, who tipped the ball into the air. Vikings cornerback Antoine Winfield intercepted it and sprinted down the left sideline.
Louis was turning toward Winfield, who passed him, and he was blindsided by Allen, who was trying to make a block. As he crumbled to the ground, Louis' left leg appeared to get caught up in the turf.
"I thought it was a legal hit. He's running to make a tackle, so I just made a block," Allen said. "I turned around, he was trying to make a tackle, and I threw myself into him. Just trying to make a block, just like we're taught.
"I'm never trying to hurt anybody. I'm trying to make a block and spring our guy. It's unfortunate."
Louis has started all 11 games this season, and he started 13 of the 14 he played in 2011. A seventh-round pick 2009, Louis is a converted tight end who has emerged as arguably the team's best offensive lineman.
The website Pro Football Focus has him rated as the team's best lineman, giving up two sacks, two hits and seven hurries. By contrast, right tackle Gabe Carimi has given up seven sacks, nine hits and 28 hurries.