For decades, the NFL was ruled by quarterbacks who did their work almost exclusively from the pocket. They scanned the field before passing the ball to receivers, throwing it away if no one was open or taking a sack if time ran out. Now the league is amid an unprecedented era of mobile quarterbacks. Depending on how that subjective term is defined, up to half of the NFL’s starting quarterbacks this season fit that mold.

There are quarterbacks who make hay on designed runs. The Falcons just faced two who gave them fits, Justin Fields (Steelers) and Jalen Hurts (Eagles). There are quarterbacks who aren’t big parts of their team’s run offense but are dangerous when they slip outside of the pocket and make throws on the move. The Falcons are set to face the best of the bunch, Chiefs quarterback Patrick Mahomes, on Sunday at Mercedes-Benz Stadium.

Then there is Falcons quarterback Kirk Cousins.

Cousins has not been much of a threat to run over his nine-plus seasons as a starter. He doesn’t often scramble away from pressure to make passes outside of the pocket. Cousins has carved a long, successful career by staying inside the tackles, surveying the field and delivering accurate passes.

With the league trending toward mobile quarterbacks, it is still possible to win big with a pocket passer like Cousins?

“I definitely think so,” said ex-NFL quarterback Chris Simms, an analyst for NBC Sports. “We just saw Brock Purdy go to a Super Bowl. The greatest quarterback we ever saw, a guy who was part of a dynasty, he couldn’t move for his life, Tom Brady.

“The guys like Lamar Jackson and Jalen Hurts haven’t proven they can win a Super Bowl, and I question if they can. Because, at the end of the day, you’re going to have to make plays from the pocket, especially when get to playoffs and the Super Bowl.”

The Falcons’ best player of all time, Matt Ryan, excelled as a pocket passer. His immediate successor, Marcus Mariota, is a mobile quarterback. The Falcons had a respectable offense built around his threat as a runner in 2022.

The Falcons had a chance to pursue a running quarterback with a league MVP award, Lamar Jackson, but declined. They explored a trade for another running quarterback, Deshaun Watson, before he went to the Browns. Ultimately, the Falcons decided that Ryan’s long-term successor also would be a pocket passer.

They signed Cousins to a free-agent contract in March. Weeks later they used the No. 8 overall draft pick on Michael Penix Jr. with the plan of him eventually succeeding Cousins. Penix didn’t offer much as a runner during college, and Cousins hasn’t done it during his NFL career.

Cousins became a full-time starter in 2015. Among the 23 quarterbacks to start at least 70 games since then, Cousins ranks 16th in rushing yards per attempt, 15th in rushing yards per game and 11th in rushing success rate (yards gained in relation to down and distance). Cousins has had some success in the past as a passer outside of the pocket, but he’s likely to be less mobile now.

He had surgery to repair a ruptured Achilles in November. Cousins didn’t move well during a Week 1 loss to the Steelers. He moved better during Monday’s victory at Philadelphia. It’s reasonable to assume that Cousins’ foot will get stronger, and that he’ll become more comfortable, but he wasn’t very mobile even before the surgery.

Said Simms: “Do you want to have a statue back there? No, of course not. You’d love to have a guy like Mahomes who can create when nothing is there. I understand that. But I saw Matthew Stafford win a Super Bowl three (seasons) ago, and he’s a pocket passer. He was playing Joe Burrow, who I also consider a pocket passer. You definitely can win big with them.”

Falcons offensive coordinator Zac Robinson agrees. He worked with Stafford for three seasons in Los Angeles. Rams coach Sean McVay has had success with pocket passers Stafford, Cousins and Jared Goff. Another of the NFL’s top offensive coaches, Kyle Shanahan, built high-scoring offenses around pocket passers Ryan, Jimmy Garoppolo and Brock Purdy.

Said Robinson: “You love those guys that can throw the ball from the pocket, knowing that those critical situations are going to come down to third downs and two-minute drives at the end of the game, where you’re going to need to throw the football from the pocket. So that’s where my eyes kind of go to is that style. It’s obviously nice to have somebody that can move around and make some plays. That’s where the combination of both is the elite of the elite.”

Mahomes is at the top of the list. He’s averaged 5.2 yards per rush during his career, fourth-best among quarterbacks with at least 70 starts since 2015. Per Pro Football Focus, Mahomes has the highest grade on passes outside of the pocket over the past two seasons. Jackson and Buffalo’s Josh Allen also thrive as runners and as passers outside of the pocket.

That combination puts a lot of pressure on defenses. Veteran Falcons safety Jessie Bates said that when facing mobile quarterbacks who can throw, there’s a designed “first part of the play” when he’s a passer and a “second part of the play” when anything can happen.

“Something I always say about (Mahomes) and a lot of really good quarterbacks is they are able to play on time and they are able to extend plays and be able to create plays with their feet and actually look downfield and still throw it,” Bates said.

Cousins excels at the on-time throws if he has good protection in the pocket. That didn’t happen much against the Steelers. It happened more often against the Eagles, including during the game-winning touchdown drive. If the Falcons can develop consistent pass protection to go along with a strong running game, then Cousins has proved to be one of the NFL’s most effective quarterbacks on play-action passes (throws after run fakes).

That formula has allowed Cousins to be an effective NFL quarterback for many years despite his relatively limited mobility. Cousins said there was a time when he wondered whether that would be possible. With mobile quarterbacks becoming the norm in the NFL, where did that leave a pocket passer like him?

Cousins said he once put the question to Matt Cavanaugh, who was his quarterbacks coach with Washington in 2015.

“I saw that (evolution) happening,” Cousins said. “More and more guys are really athletic. ‘Do I need to become a runner to keep my job, if you will?’ (Cavanaugh) said: ‘Kirk, it doesn’t matter, if you can’t throw with accuracy from the pocket, everything else isn’t worth it, especially when you get to crunch time in the playoffs.’ ...

“I would love to run through people. I would love to jump over people. But at the end of the day, those guys who have those traits have to be able to throw accurately from the pocket to truly win in the big games. ... Over the last nine years, I would say (Cavanaugh) was right.”