SANTA CLARA – Richard Sherman is not ruling out a return to action Sunday after missing the past 1 ½ games with a mid-calf strain.

Sherman took part in practice Thursday and could make a bid to get back on the field when the 49ers play the Arizona Cardinals on Sunday at Levi’s Stadium. When Sherman comes back, his return to the starting lineup will be the only thing certain about the team’s cornerback situation.

Currently, it is not clear whether Ahkello Witherspoon, Jimmie Ward or Greg Mabin would be the starter on the other side. The three took part in a cornerback rotation last week that could continue indefinitely, defensive coordinator Robert Saleh said.

Mabin entered into the picture last week to split time with Witherspoon and Ward in the 49ers’ 29-27 loss to the Los Angeles Chargers. Mabin played 29 snaps, taking 11 snaps away from Ward and 18 from Witherspoon.

“No one’s down on Ahkello at all,” Saleh said. “Mabin went in and played for Jimmie, too, and no one’s down on Jimmie. It’s more of a product of the fact that Mabin has been playing very, very well and he deserved a chance to shine.”

Mabin made a tackle and forced a fumble on his first two plays. The Chargers completed two of the four passes thrown to his side for 18 yards, according to Pro Football Focus.

“He came out and executed and played hard, he brought energy, intensity,” Sherman said. “The coaches have been talking about him for weeks. He’s had amazing days in practice. He’s been incredible, locked in and executing, so it was good to see him get his opportunity.”


When asked what it will take the 49ers to settle on one cornerback opposite of Sherman?

“One of them to grab hold of it and put a stranglehold on it and don’t let go,” Saleh said.

Starting safeties back

Backup safeties Antone Exum and D.J. Reed started last week in Los Angeles with Jaquiski Tartt (shoulder) missing his second consecutive game and Adrian Colbert being slowed with a hip contusion.

Exum returned an interception for a touchdown against Philip Rivers, but there is no question Tartt will return to the starting lineup. Reed played well against the Chargers, and coach Kyle Shanahan appeared on Monday to keep the door open for Reed to remain on the field.

But Shanahan clarified that if Colbert is ready to go, he will retain his starting job at free safety.

“We’d always lean towards Colbert, because it was his job to start with and he played at an extremely high level last year and started out this year doing that,” Shanahan said. “We believe he’s going to be much healthier this week, so I’d be surprised if he wasn’t out there.”

This ‘n’ that

Rookie linebacker Fred Warner is expecting to see a lot of Cardinals running back David Johnson, who returns this season after missing all but one game last year with a wrist injury. Warner said he expects rookie quarterback Josh Rosen to rely heavily on Johnson’s playmaking ability.

“He’s an outstanding running back,” Warner said. “They’re still trying to find ways to get him the ball and get him in the groove and get him more involved in the slot. He’s really good. Him being such a dynamic player and Josh being a rookie, I can see them getting the ball to a lot more in this game.”

Sherman said he remains optimistic about the team after C.J. Beathard steps in for injured starting quarterback Jimmy Garoppolo, who is out for the season with a torn ACL.

“He’s been really outstanding in practice,” Sherman said of Beathard. “And he’s been slinging the ball well and the receivers have been catching it. He’s been in a great rhythm. Obviously, it always sucks losing your starting quarterback, but we’re thankful we have a guy backing up Jimmy that has so much arm talent and guts.”