The San Francisco 49ers may be forced to turn to rookie Trey Lance earlier than planned.

Lance took over at quarterback for the 49ers after the half in Sunday's loss to the Seattle Seahawks.

Jimmy Garoppolo suffered a calf injury and is set for an MRI.

Garoppolo said he first felt the injury on the game's opening series. As the first half wore on, Garoppolo said the calf continued to tighten and he could feel the pain working its way down to his Achilles.

Garoppolo finished his day 14-of-23 for 165 yards with a touchdown but started 6-of-6 for 70 yards and a touchdown on the first drive. Lance finished 9-of-18 for 157 yards with the two scores for a passer rating of 117.1. He also rushed for 41 yards on seven attempts.