If the 49ers could possibly harness this quicksilver, deep-heaving NFL decathlete they’ve got for a quarterback, they might really have something in Brock Purdy.

Until then, they’ll just have to learn to live with his mad scrambles for first downs and conscience-free long passes just about every time the 49ers have the ball.

Oh, wait — the 49ers love seeing all of this wild-horse stuff from Purdy. Not just because of his undynamic reputation but because he’s actually very good — and quite a threat to defenses — when he’s pushing every piece of the envelope.

And because they need this.

“We’ve got all those weapons out there, man, why wouldn’t you?” Trent Williams said of watching Purdy repeatedly chuck deep bombs in Sunday’s cruise-control 30-13 victory over the New England Patriots at Levi’s Stadium. “It’s always good when Brock’s just unleashing the ball.”

Purdy produced five pass plays that went for 32 yards or longer on his way to completing 15 of his 27 pass attempts for 288 yards, which included a touchdown to George Kittle. These weren’t wobbly prayers. They were zipped downfield for Jauan Jennings, Deebo Samuel, and Brandon Aiyuk, right on the money as they flew through close coverage. That all produced an 89.7 passer rating, which was only that low because of the late interception, an over-aggressive attempt to get it to Aiyuk in the end zone despite double coverage. Overall, Purdy averaged 10.7 yards per attempt, his highest average of the season so far.

And when he wasn’t testing the Patriots’ backline, Purdy was dancing around the pocket, ducking rushers while surveying the field and dashing for key scrambles when there was open territory, including short runs to pick up the 49ers’ initial two first downs of the game.

Does Purdy think he’s Josh Allen or Lamar Jackson in full gallop? He’s not a tank or a sprinter. But the Patriots’ defense was dropping back to clog the middle passing lanes and not really heeding QB scrambles, and, well, Purdy has some things he can do about that.

“I’m a quarterback; I’m going to go through my reads and hit my guys and move the chains that way,” Purdy said. “That’s the position I play and I take pride in that.

“But if not, then I feel like I have just the right amount of athleticism to make plays. I don’t need to be a freak athlete and all that kind of stuff. I know who I am. But if something presents itself, then I’m willing to do what it takes for our team to move the chains with my legs.”

Brock, what do you mean by “just the right amount of athleticism”?

“I think my 10-yard split, just to give you guys some perspective, was faster than Christian’s and Deebo,” Purdy said with a smile. “I think. You can do some fact-checking. But that’s what I mean. I think I just have enough to get out of the pocket, make a play, pick up five, seven yards here or there. I’m not Lamar Jackson by any means, but …”

This recounting has taken an apocryphal place in Purdy lore (and maybe via locker-room banter), but a slight fact-check here: Purdy’s official NFL Combine 10-yard split was 1.55 seconds, according to NFL.com records. McCaffrey’s was 1.52. Samuel’s was 1.48.

It’s still comparable enough to understand Purdy’s point, though. He doesn’t look like he can beat a linebacker in a short sprint, but he can and often does. And he doesn’t mind pushing his shoulder into the defender for an extra few feet, either. Just flash back to his big runs against the Detroit Lions in the NFC Championship Game. Because Kyle Shanahan sure does.

“If he didn’t do that in the playoffs last year,” Shanahan said, “I don’t think we would’ve got to the Super Bowl.”

It’s not that big of a deal to dominate a Patriots team that looks like it will be competing for the top pick in next year’s draft. It was still important, though, that the 49ers get to 2-2 after that two-game losing streak. It was key for the 49ers’ defense to start flying around, piling up the sacks and creating turnovers. And it’s crucial that the 49ers start to counter-program what opponents have been doing to slow down their offense with Christian McCaffrey out. The 49ers still have plenty of dangerous offensive playmakers. But they need Purdy to light the fuse for it in a way that, say, Jimmy Garoppolo never really could. And this quarterback is absolutely ready for it.

Shanahan and Purdy both noted that defenses are trying to stop the 49ers’ middle-of-the-field pass attack, disrupt Purdy’s timing and load up against the running game. That can be effective enough, including during the 49ers’ loss to Minnesota two weeks ago, and in the key minutes of the loss to the Rams last weekend. That kind of defense can make the 49ers’ patterned offense look squeezed and slow and make Purdy seem limited. But it also can open up outside lanes for the 49ers’ offense to attack, either by deep pass or a QB scamper.

It gives Purdy the chance to push his own limits, and we haven’t seen that he actually has any.

“The safeties were down tight and [deep] where the ball has gotta go,” Shanahan said of two deep crossing routes that hit for big plays. “And Brock made two good throws; both the guys came down with the play.”

It’s not a brand-new wrinkle. Last season, Purdy had an NFL-best 60 percent completion percentage on passes that traveled 20 or more yards past the line of scrimmage, according to Pro Football Focus. He doesn’t have the strongest arm in the league, but he’s very accurate with the deep ball.

And Purdy is clearly more and more comfortable flinging the ball into 50-50 situations and letting his guys fight for it. Jennings has proven the wisdom of this approach over the last few elevating weeks. Kittle’s TD catch, over and around three defenders, was incredible. The interception to Aiyuk was just a split-second off.

“We have all the pieces,” Nick Bosa said. “Obviously, Brock is playing his butt off. And guys are making plays for him. … I love seeing it. I love seeing Jauan make plays, Deebo, George. It’s tough to spread it around.”

The 49ers can win a lot of games like this. Then, whenever they get McCaffrey back, they can roast whatever defense they face. But it starts with Purdy now. He’s driving the bus. He’s making the big stuff happen. And everybody on the team is loving it.