Rams will be without cornerback Aqib Talib when they face some of the NFL’s best quarterbacks ... and CJ Beathard

With his surgically repaired left ankle encased in a plastic protective boot, Aqib Talib sat on the Rams’ bench in Denver last week and offered moral support.

Talib’s absence since suffering the injury in Week 3 left a void in the Rams’ defense. And the veteran cornerback is at least five weeks away from possibly returning to help a secondary that has missed his leadership, experience and performance.

In the Rams’ 23-20 victory over the Broncos, Case Keenum challenged replacement starting corner Troy Hill several times to complete passes for long gains and a touchdown.

“I can play better,” Hill said Wednesday. “Had a couple plays, but just keep going.”

Hill and Rams cornerbacks could be tested again Sunday when the Rams play the San Francisco 49ers at Levi’s Stadium.

Before the season, the game mapped as a showcase for Rams quarterback Jared Goff and 49ers quarterback Jimmy Garoppolo. But Garoppolo suffered a season-ending knee injury in Week 3, elevating second-year pro CJ Beathard to starter.

Beathard has neither the name recognition nor resume of Kirk Cousins, Russell Wilson or Keenum, but he showed in Monday night’s 33-30 defeat to the Green Bay Packers that he can be effective.

Beathard completed 16 of 23 passes for 245 yards and two touchdowns, with an interception, before Packers quarterback Aaron Rodgers engineered a game-winning drive for a field goal.

Beathard’s performance probably did not strike fear into the hearts of a Rams team that is 6-0 and ranked seventh in the NFL in scoring defense, giving up 19.7 points a game. The Rams rank ranked 11th in total defense, 13th in passing defense and 14th in rushing defense.

But the secondary can improve, safety John Johnson said.

“I feel like we’re playing all right,” said Johnson, who intercepted a pass against the Broncos. “Not to the level that we could be playing, but that will come.”

The Rams would benefit from consistently strong play at both cornerback spots.

After Talib was injured against the Chargers, defensive coordinator Wade Phillips started Sam Shields opposite Marcus Peters against the Minnesota Vikings.

Peters, playing four days after suffering a calf strain, was clearly not himself. On a Cousins pass to receiver Aldrick Robinson, Peters leaped to break up the play but could not get his usual lift.

Cousins and his receivers exploited Rams cornerbacks throughout the game, amassing 422 yards passing and three touchdowns, but the Rams hung on for a victory.

The next week, Hill started opposite Peters.

While Peters struggled for the second week on a row — Seattle’s Wilson passed for 198 yards and three touchdowns — Hill played well in the Rams’ 33-31 victory.

But last Sunday at Denver, Keenum went after Hill while passing for 322 yards and two touchdowns.

Broncos receiver Emmanuel Sanders caught a 43-yard pass, and Demariyus Thomas and Courtland Sutton also made big catches with Hill defending.

Coach Sean McVay described them as “contested-type plays” that did not reflect poorly on Hill.

“It’s one thing if you’re just getting beat, it’s another thing when you’ve got guys that are going up and some 50-50 balls,” McVay said. “Those aren’t plays that you say, ‘Man.’

“Troy Hill is a good player that’s made a lot of plays and he’s winning those opportunities more times than not.”

Said Hill: “I feel like it was on me and my technique, and things like that I can clean up and go out and fix.”

The Rams defeated the Broncos, but the cornerback situation could remain an issue before Talib potentially returns for a Week 13 game at Detroit, which follows an open date. After the 49ers, the Rams face four huge quarterback challenges: Rodgers, the New Orleans Saints’ Drew Brees, Wilson and the Kansas City Chiefs’ Patrick Mahomes.

Safety Lamarcus Joyner said the “big personalities” in the secondary are starting to jell. A goal, he said, is to be playing well in the second half of the season.

“They remember November,” Joyner said.

And later, Johnson said.

“I want our best football to be played December, January and February,” he said. “I feel like we’ll get there.”

Etc.

A day after putting kicker Cairo Santos on waivers, McVay sounded excited about the return of kicker Greg Zuerlein. “Got the full clearance, thumbs up,” McVay said. “So, that was why we made that decision and feel good about Greg moving forward.” Zuerlein, however, sounded less certain when asked what it felt like to return from a groin injury. “I’m not back yet,” he said. “Still got to practice this week and see how it goes, see how it feels. Hopefully, it feels good.”… The Rams will wear their gold-yellow “color rush” uniforms Sunday.

gary.klein@latimes.com

Follow Gary Klein on Twitter @latimesklein