ATLANTA -- Falcons fullback Ovie Mughelli's season is over.
The Falcons placed Mughelli on injured reserve on Tuesday. Mughelli, a 2010 Pro Bowl selection, hurt his right knee in the fourth quarter of Sunday's 23-16 win at Detroit. He suffered the injury when hit by Lions defensive back Louis Delmas.
The Falcons also placed backup offensive guard Mike Johnson on injured reserve with a foot injury. Johnson, a third-round pick from Alabama in 2010, has played in two games this season.
Cox, from Georgia Tech, played for Kansas City the past three seasons. Chambers, from Stanford, has not played in the NFL since 2009. He played with Cleveland and Buffalo from 2004-09 and was released by the Lions before the start of this season.
Coach Mike Smith said Monday that Jason Snelling would move up at fullback if Mughelli's injury was serious.
"Jason's had to do this before," Smith said. "Last year, we missed Ovie when he was injured in the San Francisco game. He stepped right in and our offense didn't miss a beat.
"Jason stepped in (Sunday) into a no-huddle situation where he was playing fullback and we were running our no-huddle offense and we didn't miss a beat. Jason has done it in the past and he's very familiar and that's one of the reasons we have him on our roster because he gives us flexibility to play both the fullback and the halfback."
Mughelli was hurt after making a catch for 4 yards. It was a rare opportunity for the blocking back who had four catches for 25 yards and two touchdowns and only two carries for one yard this season.
Mughelli tweeted Monday the injury was not as bad as it appeared.
"Thx for all the love and support guys," OvieMughelli34 tweeted. "I promise I'm ok. It looked worse than it is. I heard the slo mo looked bad on tv. I'll b back soon."