PHILADELPHIA -- Already down to their third-string quarterback, the San Francisco 49ers had to turn to their fourth option in the first quarter of Sunday's NFC Championship Game against the Philadelphia Eagles.

Niners quarterback Brock Purdy suffered a right elbow injury on San Francisco's sixth offensive snap. He's considered questionable to return.

Veteran signal-caller Josh Johnson replaced Purdy on the 49ers' next drive, which resulted in a three-and-out.

Purdy sustained his injury with 7:03 left in the opening quarter. Facing second-and-6 at the 50, Purdy dropped back to throw, looking for wideout Brandon Aiyuk down the left side. Eagles pass-rusher Haason Reddick raced past Niners tight end Tyler Kroft and hit Purdy as he attempted to throw, jarring the ball loose. It bounced off Purdy's elbow and flew forward to Philadelphia's 44, where Eagles defensive tackle Linval Joseph recovered.

Purdy initially attempted to return to the game, but coach Kyle Shanahan stopped him and sent Johnson in as Purdy retreated to the blue medical tent for further evaluation. Purdy, who became the fifth rookie quarterback to start a conference championship game, was 2-of-2 for 19 yards at the time of the injury.