Texans coach Gary Kubiak said quarterback Matt Schaub will be an end-of-the-week decision as he recovers from injuries to his "leg, ankle, everywhere."
Kubiak also indicated the injury to the much-maligned Schaub could have been worse.
"We'll have to see where we're at," Kubiak said Monday, when asked directly whether Schaub would start Sunday if healthy. "I gotta see if he's healthy."
Kubiak also revealed Schaub received injections Monday.
"Matt is actually getting some injections as we speak," Kubiak said. "Obviously he's very sore and beat up on the leg, ankle, everywhere.
"We'll have to see where he's at, but probably got a little bit lucky there."
Schaub suffered an injury to his lower right leg during Sunday's loss to St. Louis when he was sacked in the third quarter by Rams defensive end Chris Long.
Long celebrated the sack but later said on Twitter that he wouldn't have if he knew Schaub was hurt.
A group of fans in Houston cheered when Schaub suffered the injury, and a larger group of fans cheered when Yates entered as the backup.
Schaub left the game having completed 15 passes for 186 yards with no touchdowns and no interceptions. He had thrown nine interceptions in the previous five games, including four that were returned for touchdowns.
Against the Rams, Yates threw two interceptions, one of which was returned 98 yards for a touchdown.
Yates, a Texans draft pick in 2011, entered the season as Houston's backup quarterback. Keenum, who has been inactive for the first six games of the season, entered as the team's third-string quarterback.
The Texans kept only two quarterbacks on their active roster last season and kept Keenum on their practice squad. His performance during this year's training camp and preseason earned him a place on the active roster.