For the second time this season, rookie Dwayne Haskins was forced into a game in which it wasn’t expected he would play, and after another uneven performance, it’s unclear when he will be given the full-time opportunity to be the Washington Redskins’ starting quarterback.

The 15th pick in this year’s draft started the second half after Case Keenum was diagnosed with a concussion at halftime and finished 3 for 5 with 33 yards and an interception and was sacked twice in Washington’s 19-9 loss to the Minnesota Vikings. Haskins didn’t seem completely overwhelmed, but he didn’t look fully comfortable, either. The Redskins managed just three first downs in that second half, and one was Wendell Smallwood’s 11-yard rush on the final play of the game.

He stood stone-faced as he addressed reporters in his postgame news conference, still in his game attire, minus his shoulder pads and jersey. Moments before, running back Adrian Peterson had stopped him and offered some words of advice.

“He’s here for me,” Haskins said were Peterson’s words. “I can rely on him. … Wants me to own it, and I do.”

His worst moment of the game came after the Redskins’ defense had made what seemed to be a critical stop of Minnesota as it attempted a fourth-down conversion in its own territory. Washington took over on the Minnesota 34-yard line, but on the second play after taking over, Haskins threw too high for rookie wide receiver Terry McLaurin — his Ohio State teammate — and was intercepted by the Vikings’ Anthony Harris.

At a minimum, the offense should have gotten a field goal on the possession to cut the lead to 16-12, but the Redskins left the field with zero and never moved the ball that deep into Vikings territory again.

Haskins said he couldn’t step into the throw, and the ball sailed. Interim coach Bill Callahan said the play call was excellent, the route was good and Haskins’s read was correct but called the result “unfortunate” and “something to learn from.”

“No question he’d like to have that one back,” Callahan said. “… It’s a growing process with any young quarterback coming into the league.”

The next question is when that growing process will continue for Haskins on the field. Callahan said that Keenum will be the starter for next week’s game at the Buffalo Bills if he’s healthy but that Haskins is the team’s No. 2 quarterback and will start over veteran Colt McCoy if Keenum is unavailable.

But with the team’s record now at 1-7, it seems to be getting closer to the time for Washington to fully commit to Haskins’s development by handing him the starting job.

Defense shows up, but depth and injury issues are again on display

The Vikings entered Thursday night’s game as the sixth-ranked offense in the league, averaging 27.4 points and 391.1 yards. On the whole, the Redskins’ defense held up well against the challenge. Defensive linemen Jonathan Allen, Matt Ioannidis and Daron Payne were all active throughout (Payne ran 40 yards to get back into the play on which Vikings wideout Stefon Diggs fumbled following a 32-yard catch), and the unit allowed just one touchdown even though Minnesota moved inside the Washington 35-yard line six times, giving the team a chance to win.

But a few key plays they gave up put on display their injury issues in the secondary, which only got worse as the game went on. Starting safety Montae Nicholson didn’t play, and cornerback Josh Norman was far from 100 percent. Norman was active after missing last week’s loss to the 49ers but didn’t play until a hamstring injury took starter Quinton Dunbar off the field. The injury situation at the safety position, already without Nicholson and Deshazor Everett, got even worse when Jeremy Reaves also left the game with a concussion. Diggs was able to take advantage, getting loose for seven receptions and 143 yards.

The final drive was a killer, as well,. The Redskins couldn’t get off the field to get the offense the ball back, including a third-and-19 conversion on a draw play on which backup safety Troy Apke couldn’t get Vikings running back Alexander Mattison on the ground.

The defense has made strides since giving up 33 points to the Patriots in Week 5, but it’s not a particularly deep unit. If the injury issues continue — particularly if Dunbar misses time — it’s unlikely the results will be different.

Peterson gets emotional

The in-stadium camera zoomed in tight on Peterson late in the fourth quarter, and the crowd roared with an “AP! AP!” chant to acknowledge the future Hall of Famer and former Vikings great.

This was the organization for which Peterson had his biggest triumphs, and on Thursday he passed Jerome Bettis and LaDainian Tomlinson to rise to sixth on the NFL’s all-time rushing list. Peterson smiled at the recognition before kissing and pumping his fist, index finger extended.

“Just love,” Peterson said. “Even in a moment of defeat, was able to embrace it. … It was a special moment. Holding tears back, to be honest with you.”

Peterson finished with 76 rushing yards and 27 receiving yards as he was again the focal piece of the offense under Callahan.