49ers QB Brock Purdy’s legs ‘the difference between us winning and losing’

SANTA CLARA, Calif. — The narrative was that the San Francisco 49ers couldn't come from behind in the Kyle Shanahan era.

But during this season's playoffs, they've dispelled that notion with two big-time comeback wins to advance to the Super Bowl.

On Sunday, a major catalyst for San Francisco's 34-31 victory over the Detroit Lions was the legs of quarterback Brock Purdy, who finished with 48 rushing yards. 

"It's just amazing because I don't think too many people know how fast and elusive Brock is until he gets to running," Deebo Samuel said. "I think I kind of messed up one of his touchdowns trying to get a lead block, and he ran right into me and bounced off. I feel like if I would have made that block, he probably would have scored." 

According to Next Gen Stats, Purdy converted three first downs on scrambles and completed 3-of-4 passes for 41 yards and three first downs on passes when he scrambled outside the pocket.

The second-year quarterback said getting outside the pocket and using his legs is nothing new.

"My job is to distribute the ball to guys that are open," he said. "Then if something is not there, especially in this kind of game, you got to find a way.

"I feel like throughout my life I've scrambled here and there. Since I've been here, I feel like I haven't done it a whole lot. [On Sunday night], I was just trying to keep the chains moving, keep the ball moving forward and then give our team some momentum and some juice."

Purdy will never be mistaken for Lamar Jackson or Josh Allen. The Iowa State product finished with just 144 rushing yards during the regular season. Of course, when you have explosive runners like Christian McCaffrey and Samuel, it makes more sense to design plays to get them the ball in space. 

"Sick," tight end George Kittle said when asked about Purdy's scrambling. "Do it more … just don't get hit. Like, maybe tuck the ball a little faster. He scampers — I think that's the best way to describe it. You ever seen one of those little water dragons running across the water? That's what I envision every time he's running with the football."

San Francisco offensive lineman Colton McKivitz, however, says Purdy is a surprisingly good runner, which adds another dimension to the team's already explosive offense.

"It's him trusting his legs — the more you can do. There's guys like [Patrick] Mahomes that we're going to see. Obviously, Lamar [Jackson], he's a lot slower," McKivitz said with a laugh. "But it gives us another threat and just that extra little thing that the defense has to account for with a guy that can run."

While Kyle Shanahan won't be building an inventory of designed runs for his QB, the San Francisco head coach was extremely thankful for the plays Purdy made against the Lions by scrambling. 

"I thought it was the difference between us winning and losing," Shanahan said. "He made some big plays with his legs, getting out of the pocket, moving the chains on some first downs, some explosives.

"He competed his ass off. Wasn't easy for any of us. He kept grinding and was unbelievable there in the second half." 

Eric D. Williams has reported on the NFL for more than a decade, covering the Los Angeles Rams for Sports Illustrated, the Los Angeles Chargers for ESPN and the Seattle Seahawks for the Tacoma News Tribune. Follow him on Twitter at @eric_d_williams.