Peterson was released by Washington on Friday, and because the Lions had kept private the significant health concerns they have about their backfield, they were able to pounce quickly on the NFL's fifth all-time leading rusher.
Peterson is 35 years old and no longer the workhorse runner that steamrolled the Lions with the Minnesota Vikings for a decade, but he can be an effective part of a backfield-by-committee in Detroit this year.
The Lions have been on a two-decade-long quest to fix their running game, since Barry Sanders retired after the 1998 season, and under general manager Bob Quinn have spent six picks in the past five drafts on the position, including two second-rounders, and have unsuccessfully taken fliers on a trio of washed-up veterans (Stevan Ridley, LeGarrette Blount and C.J. Anderson).
It's possible Peterson ends up in the latter category. Washington released him to go with a Peyton Barber-Antonio Gibson-Bryce Love-J.D. McKissic backfield that hardly strikes fear in opponents.
But for a Lions team whose top three options — Kerryon Johnson, D'Andre Swift and Bo Scarbrough — all missed time this preseason because of injuries, Peterson almost certainly will be a big part of the game plan starting with next Sunday's season opener against the Chicago Bears.
The Lions drafted Swift in the second round to eventually take over as their lead back, and nothing has changed with their hopes that happens.
Swift suffered a soft-tissue leg injury in the first week of padded practice and has practiced sparingly since. He's dynamic with the ball in his hands, a capable receiver who should be a weapon on third downs this year, but has missed enough time that his offensive coordinator openly wondered how much of a workload he'll be able to handle early in the season.
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"It’s not ideal, we’ll say that," coordinator Darrell Bevell said one week ago. "There’s a lot on these rookies’ plates right now just in terms of everything’s new for them. Obviously, he’s trying to pick up a whole new offense and we did not have the offseason. I think that’s what’s so critical and every day that we miss, I think it puts you further behind in terms of, not necessarily just knowing your assignment, but then it’s how your assignment fits to each and every one of the looks that you can get from the defense.
"It’s one thing to see them on paper, it’s one thing to see them on tape, but it’s another thing to go out there and actually execute what you’re supposed to execute, make the decisions that you’re supposed to make at a quick level, and he’s missing all those different reps."
While Swift's injury could potentially linger into the season if he's not handled carefully, it's Johnson's knees that are a bigger concern.
Johnson missed six games as a rookie in 2018 and eight last year with two different knee injuries, and the Lions managed his reps judiciously this summer.
They hope he can return to the same explosive form he showed as a rookie, when he averaged 5.4 yards per carry and led the team in rushing. But Sunday's signing of Peterson shows how deeply they're concerned.
Scarbrough gave the Lions' rushing game a jolt last season when he signed off the street and rushed for 98 yards a week later against Peterson's Washington team. (Peterson gave Scarbrough his jersey after that game, and the jersey hung proudly in Scarbrough's locker the rest of the year.)
But Peterson should usurp whatever carries the Lions had planned for Scarbrough on the goal line and in short-yardage situations, where his physical running style has not dissipated with age.
There is upside for both Peterson and the Lions with this move.
Peterson earned his Hall of Fame credentials with the Minnesota Vikings, where his coordinator for the first four seasons of his career was Bevell.
Peterson averaged 1,446 yards rushing and 13 touchdowns a season under Bevell, and while it's completely unreasonable to expect a return to that level of production, there should be comfort for both player and coach in their familiarity.
Peterson has a chance, too, to further cement his legacy as one of the NFL's greatest ever running backs. He needs 1,054 yards to pass Sanders for fourth place on the all-time rushing list, and there's an outside chance he gets that done in a Lions uniform this year.
If Peterson stays healthy, I expect he and Johnson will share one role in the Lions' backfield-by-committee, with Swift the other half and in line for expanded playing time as the season goes on.
Swift is the future, and the key to improved production from the running game this fall. If he's not a quick study, it will be detrimental to the offense.
But by signing Peterson, the Lions gave themselves another option for a running game that remains the weak link of an otherwise potent offense, and heading into a season full of question marks, there's nothing wrong with that.
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This article originally appeared on Detroit Free Press: Detroit Lions sign Adrian Peterson: What it means for rest of RB group