Fourth-string QB Josh Johnson leads 49ers to Christian McCaffrey TD

Christian McCaffrey is carrying the 49ers offense with Brock Purdy out

In the unlikely season for the San Francisco 49ers, this has to be one of the most unlikely stories in NFL history.

Third-string QB Brock Purdy, who was the first-string QB after injuries to Trey Lance and Jimmy Garoppolo, went down with an elbow injury in the NFC Championship Game against the Philadelphia Eagles on Sunday against the Linc.

On came journeyman Josh Johnson, who has been on 13 or so teams in a whirlwind career.

Johnson knew what to do: give the ball to Christian McCaffrey.

McCaffrey accounted for 44 of the 46 yards on the 6-play drive that ended with his touchdown.

The Robbie Gould PAT tied the game at 7 in the second quarter.