NINERS' NADIR

Purdy left the game with an elbow injury after he was drilled in the arm by Reddick on San Francisco's first drive. The play was initially ruled an incomplete pass, but replays confirmed it was a fumble.

"I knew that was a sack-fumble because I got my hand on the ball," Reddick said.

He also got his hand on Purdy's arm, changing the course of the game. The 23-year-old Purdy's improbable rise from "Mr. Irrelevant" to playoff starter ended with a whimper as he failed to become the first rookie QB to lead a team to the Super Bowl.

He was improbably needed again in the third quarter after Johnson, a journeyman backup signed in December, was also injured.

"I hurt for these guys," Shanahan said. "We felt really good about this game. It was tough circumstances." With little hope they could get anything going behind Johnson, the 49ers turned to Christian McCaffrey, a midseason acquisition who led the team with 13 TDs in the regular season and playoffs, to get on the board. He broke three tackles on a 23-yard touchdown run that made it 7-7 in the second quarter.

That turned out to be the only moment of hope for Shanahan's Niners, who managed 164 yards of offense and 11 first downs.

"You're never out of the fight," McCaffrey said. "We believed it and it just didn't turn out our way. We got beat and wish we had another shot at it with everybody."