Cornerback Trumaine Johnson and left guard Chris Williams also were sidelined with blows to the head, but will be available against the 49ers.
All three returned to practice in a limited role Thursday, then were full participants Friday at Rams Park.
None of the three Rams who left against Chicago made it back into the game. Williams left in the second quarter. Stacy and Johnson both were hurt in the third period.
All three have been cleared to play against San Francisco (7-4).