Third-round cornerback Kendall Fuller and safety Duke Ihenacho try to bring down Packers wide receiver Randall Cobb, as second-round pick Su’a Cravens trails the play. In a key Week 17 game, Washington will get almost no contribution from its draft class. (Jonathan Newton/The Washington Post)

As the Washington Redskins enter the regular season finale, poised to battle for a playoff berth and needing meaningful contributions on all fronts, their draft class will end the year with a whimper.

Injury again will overshadow promise as second-round pick Su’a Cravens — the brightest star among Washington’s draft selections for much of the season — is expected to miss the finale because of the lingering effects of an elbow strain that has forced the linebacker to sit out the past two games.

Cravens this week finds himself in the same situation as Josh Doctson, the first-round pick who has spent the bulk of the year on the shelf because of Achilles’ tendon injuries.

And so, in contrast to last season, when members of the 2015 draft class (Brandon Scherff, Preston Smith, Jamison Crowder and Kyshoen Jarrett) offered strong late-season contributions, the Redskins will have to wait until sometime next year to know for sure what they have in their 2016 class.

“It’s hard when your number one guy [Doctson] hasn’t been able to play,” Redskins Coach Jay Gruden said. “It’s been disappointing for everybody, but I still think he’s going to be a dynamic player for us for a long time. Su’a, we knew coming in he was going to be a guy that we teach him the defense and he’d be a jack-of-all-trades kind of guy but can run, he’s 21, teach him something he can grasp on to and let him branch off. Those two guys, you can’t see the rewards until two or three years down the road.”

Su'a Cravens is mobbed by his teammates after a game-ending interception in Week 3, but there weren’t many other standout plays by draft picks this season, although undrafted rookie Rob Kelley has shined. (Toni L. Sandys/The Washington Post)

Cravens’s injury leaves third-round pick Kendall Fuller as the top healthy draft pick, although he too is unlikely to play a key role Sunday — for a different reason. After a tumultuous ride at nickelback in the second half of the season, Fuller was benched two weeks ago, and he plays primarily on special teams now. Fifth-round pick Matt Ioannidis only sees a few snaps a game behind veteran defensive linemen. And sixth-round pick Nate Sudfeld never dresses as the third quarterback.

Gruden, General Manager Scot McCloughan and their assistants like the potential that Fuller and the remaining draft picks offer. Coupling that promise with the contributions from two undrafted players, running back Rob Kelley and wide receiver Maurice Harris, Gruden described this year’s crop of rookies as “a solid group.”

Although the wait-and-see approach isn’t particularly devastating, the team certainly had hoped for more. By this point in the season, the rookies should have worked their way into meaningful roles that would point to bigger ones in 2017.

Doctson wasn’t expected to overtake veterans Pierre Garcon or DeSean Jackson in the starting lineup. But by now, the Redskins wanted him to carve out a role as a go-to red zone weapon, using his height, athleticism and impressive leaping ability to snag fades and jump balls in the end zone.

Although undersized for the traditional inside linebacker position, Cravens spent the regular season taking snaps there in nickel packages. But brass had hoped the Southern California product would be using his ball-hawking skills all over the field by now.

Before his latest injury, Cravens missed time because of a concussion. That injury came in Week 4, a week after Cravens made his best play of the season — a game-sealing interception against Eli Manning and the Giants. He missed the following two games, and that time off stunted his development.

Early this week, Gruden confirmed plans to move Cravens to strong safety for the final game of the season — a move that would have both addressed a need with Donte Whitner struggling and injured and given Cravens a head start on his full-time job for 2017. But a lack of progress in his recovery foiled those plans.

Defensive coordinator Joe Barry said he didn’t know how effective Cravens could have been at safety given limited prep time. He described Cravens’s season as “up and down.”

“Missed [2½ ] games with a concussion and now has missed three games with the arm,” Barry said. “Of course, frustrating for him because he wants to be out there and wants to play. It’s been frustrating for all of us. He’s a very good gap player who has a great, exciting future. But I’m greedy. I want to use him now. So, frustrating.”

But the temporary frustrations could subside.

“Well, first, they didn’t draft guys to get injured, so that’s tough,” said former Redskins and Houston Texans general manager Charley Casserly, who now works as an analyst for NFL Network and CSN Mid-Atlantic.

Casserly stressed the importance of patience. Doctson has the skill set to develop into an effective wide receiver, he believes, and Cravens could become an impact strong safety or at least a versatile hybrid contributor. And Casserly said he believes Fuller could become a starting cornerback.

But it normally takes more than a year to grade a draft class, Casserly explained.

“Tom Landry had a theory, and it was a three-year program,” said Casserly, who, according to his research during a 10-year study, believes there’s only a 30 percent chance of landing a bona fide starter in the draft. “Year 1, we get them here. Year 2, we want to see improvement. Year 3, you want to see them play. If they’re not playing in Year 3, then we’re going to start the process all over again. That’s a good way to look at the thing. It’s an investment. It’s time. You have to be patient. You want to see some of the things in them that you saw when you drafted them. Hopefully they did those things. I didn’t see enough of Doctson to know. But I did see the positives in Cravens and Fuller that I saw in college.”