The Rams promoted WR Danario Alexander from the practice squad on Tuesday after officially placing WR Mark Clayton on the season-ending injured reserve list.
Clayton suffered a torn patellar tendon in his right knee in Sunday's loss to the Lions.
The Rams also promoted LB/FB Brit Miller to the active roster.
TE Darcy Johnson was placed on injured reserve. Johnson appeared in four games with two starts this season. He left Sunday's game with concussion-like symptoms. PFW correspondent and St. Louis Post-Dispatch writer Jim Thomas said the Rams will probably seek an injury settlement with Johnson.
The way we see it
Alexander, a rookie, will have a lot of appeal in the area because he is a Missouri star, but he won't make much of an impact. If he's healthy enough to make the roster, he could be a surprise contributor but is likely there for depth. Miller is a workaholic and was a special-teams contributor with the 49ers. Johnson was mostly a blocker and the good news is that rookie TE Michael Hoomanawanui is supposed to come back sooner than expected. He was the team's leading receiver in the preseason.