Coach Scott Linehan said Hill was hurt yesterday near the end of practice and will be re-evaluated next week.

"The best-case scenario is probably two games," he said.

Hill joined a growing list of key Rams players who have been hurt already.

Lenny Walls, signed as a free agent from Kansas City during the offseason, will start in Hill's place Sunday at home against San Francisco (1-0).

The Rams (0-1) have already lost left tackle Orlando Pace for the season after a shoulder injury in Sunday's 27-13 loss to Carolina.

Guard Richie Incognito will miss his second straight game with a high ankle sprain. Backup tackle Todd Steussie will miss at least half of the season with a broken foot sustained in the preseason. Linebacker Pisa Tinoisamoa, who hurt his ankle against Carolina, is listed as questionable.

Hill, the Rams' top pick in the 2006 draft, knew right away the injury was serious. It happened when Hill and safety Oshiomogho Atogwe ran into each other on a passing drill.

"I couldn't breathe at first," Hill said.

Walls played nickel back against Carolina and was confident in preparing for the start.

"I've played this game for six years," he said. "It's no big deal to me. I'm relaxed and ready to go."

Rookie Jonathan Wade will take Walls' spot as nickel back.

"The next guy goes in," he said. "There's no devastation. That's why you have a full roster. Injuries are part of the game."

The injury to Hill leaves St. Louis with just three cornerbacks. Linehan said a roster move will be made this weekend. Fakhir Brown is serving a four-game suspension for violating the league's substance-abuse policy.