Running back Adrian Peterson rushed 11 times for 56 yards in his Redskins preseason debut. (John McDonnell/The Washington Post)

All eyes were on Adrian Peterson, the new accessory in the Washington Redskins’ game-day arsenal. After months of waiting for any sign of interest from an NFL team, Peterson finally received the news this week he had longed to hear: He was wanted. And when Peterson grabbed hold of the football for the first time in nine months against the Denver Broncos on Friday night, donning burgundy and gold for the FedEx Field crowd, the 33-year-old running back did not disappoint.

It was vintage “All Day” — an exhilarating blend of burst, shiftiness and vision. The man whom so many believed was done, showed flashes of the Peterson of old, the running back who was once the league’s best.

“So many years, I’ve begged to play in the preseason and was shut down,” he said, smiling. “So, they didn’t have to beg me to play to all.”

Unfortunately for Redskins Coach Jay Gruden, the player he plucked off the street only days ago was the lone bright spot in an otherwise inept 29-17 loss to the Broncos.

Washington’s first-team offense was woeful behind starting quarterback Alex Smith, who went 3 of 8 for 33 passing yards and struggled with timing.

“Not where it needed to be,” Smith said, giving an assessment of his performance. He was replaced by Colt McCoy (3 of 8 for 19 yards) late in the first half. “. . . You expect to go out there and execute.”

The unit, ineffective in the passing game, was just 1 for 11 on third-down conversions.

“I wish we had done a little bit better job in the passing game,” Gruden plainly said, adding that his plan was to give his starters on offense “three or four drives no matter what. . . . My whole intent is to get our starting group to [Week 1] Arizona healthy and it looks like that’s what we’re on pace to do right now.”

Meanwhile, Denver gashed the Redskins’ revamped defense, which allowed rookie running back Royce Freeman to scamper 24 yards for an early score and later allowed wide receiver Emmanuel Sanders to break free for a 27-yard touchdown run.

Aside from a 33-yard Dustin Hopkins field goal, the Redskins mustered only two offensive scoring drives, both courtesy of their third-string quarterback Kevin Hogan. The McLean native capped a six-play, 78-yard drive with an 18-yard scoring pass to rookie wide receiver Simmie Cobbs Jr., and then finished off another touchdown drive in the game’s final minute with a four-yard touchdown toss to wide receiver Darvin Kidsy.

But the stage belonged to Peterson.

Glimpses of his illustrious past were evident on the very first play from scrimmage, when he high-stepped through an opening paved by the Washington offensive line and gained seven yards up the middle on his first carry. His effort energized fans in the half-full stadium, but it was wasted by a Broncos’ sack of Smith and a Vernon Davis drop on third down that caused a three and out.

The veteran running back also was the featured attraction on Washington’s second offensive series, carrying the ball seven consecutive times. Peterson rumbled for gains of six and 13 yards on the same first-quarter drive, but his most explosive play was a 15-yarder that was the aided by a quick bounce outside and a stutter-step to avoid a Denver defender being blocked out of bounds by Davis.

Peterson knew to be patient, watched the play develop and then noticed the outside was wide open. “I turned on the speed a little bit, got around and tried to make a big play out of it,” said the running back, who immediately was embraced on the sideline by Redskins left tackle Trent Williams, his former teammate at Oklahoma.

A defiant Peterson stood behind the lectern just a few days ago and informed the football world that he still had plenty left. And after only two practices with his new team — and no training-camp he showed why he just might be an intriguing option in 2018.

Following Thursday’s team walk-through practice at Joint Base Andrews, Peterson made it clear that he was prepared for any workload Gruden would give him.

“Whatever they allow me to get,” Peterson said. “I wasn’t able to participate in OTA’s or training camp anywhere, so all work for me going forward is good work.”

When it was all said and done, Peterson had rushed 11 times for 56 yards.

By halftime, Washington trailed 17-3 and as the Broncos continued to tack on more points, questions remained about the efficiency of the Smith-led offense, which was without several key pieces, including Jordan Reed, Jamison Crowder and Chris Thompson.

“Any offense is going to be better with all the weapons out there. Of course. And I’m hopeful we’ll have them all out and be ready to roll. . . . If not, we’ve still got to go and find a way to put points on the board.”