The San Francisco 49ers' injury concerns on the left side of its offensive line continued early on during Sunday's contest against Chicago.

Thrust into the lineup as the 49ers' starting left guard, fifth-year pro Ben Bartch exited San Francisco's Sunday date against Chicago with an ankle injury. Bartch was taken straight into the blue tent for further examination.

ESPN's Nick Wagoner reported that Bartch is questionable to return.

Bartch had been inserted into the lineup as the 49ers' starting left guard because fourth-year offensive guard Aaron Banks continues to recover from a concussion.

Spencer Burford replaced Bartch at left guard. Burford was San Francisco's starting right guard each of the past two seasons.

Bartch exited with San Francisco (5-7) in possession of an early 7-0 lead over Chicago (4-8).

San Francisco capped its opening drive of the contest with a 7-yard touchdown pass from quarterback Brock Purdy to wide receiver Jauan Jennings. That was the finishing touches on a 5-play, 70-yard touchdown drive.