Defensive end — Jarvis Jenkins

A year ago at this time, Jenkins was the talk of training camp and was on the verge of delivering the first of his three tremendous preseason showings. A season-ending knee injury in week-three of the preseason kept the former Clemson standout from helping the Redskins in any regular season games in 2011, but the second-year defensive lineman will begin his second ‘rookie’ season in Buffalo tonight.

Jim Haslett said that Jenkins — drafted 41st overall last April — struggled during OTA’s and got off to a slow start in training camp. That’s natural for somebody still working his way back from a devastating knee injury that cost him an entire campaign. The 315-pound, run-stuffer has performed much better in practices over the last week, and according to Haslett he’s finally returned to the pre-injury form that resulted in him being considered “the Redskins’ best defensive lineman” during camp a year ago.

Jenkins plays both end spots and will also see time at nose tackle during passing situations. His versatility along the defensive front makes him an invaluable piece to Washington’s rotation. He’ll serve as the top reserve to both Adam Carriker (left-end) and Stephen Bowen (right-end) and he’ll also allow Haslett to play Barry Cofield a little bit less this season, which should keep the former New York Giant fresher. (Nose tackles generally play about 55 percent of snaps, a number Cofield exceeded last season).

If Jenkins is right when he’s on the field tonight, you’ll see a guy who is capable of generating a steady pass rush from the defensive line. You’ll see a giant defender collapsing the pocket from the interior, forcing quarterbacks to slide out of a crumbling pocket. Keep your eyes open for No. 99 tonight, as Jenkins plays in his first game since last August.

Linebacker — Keenan Robinson

Robinson has plenty of learning to do, and there is no better way to indoctrinate himself into Washington’s 3-4 scheme than during game action. A supremely athletic linebacker with good instincts and a plus running ability, Robinson will be competing to win a job as a backup linebacker during the preseason. If everything goes well, he’ll make Washington’s 53-man roster and play an extensive role on special teams during his rookie year.

The 119th player chosen in April’s draft, Robinson played in a 3-4 defense at Texas but he spent the majority of his time as an outside linebacker. The Redskins are moving the fourth-round pick inside, where they thing his ability to shed blocks and run laterally will better suit the team’s defense. I view Robinson as a quality prospect and a nice project. He is what Perry Riley was a couple seasons ago; a mid-round pick who possesses all the skills necessary to become a quality NFL linebacker.

It took Riley a year and a half to take over a starter in Washington’s linebacking corps, partially because Riley was hindered by not having authentic offseasons to best prepare him for training camp over the past couple seasons. Robinson won’t have to deal with a lockout so his learning curve shouldn’t be as steep or arduous as Riley’s was, but he’ll still have to master both of the Redskins’ inside-linebacking positions. He’ll need to know all of the jack-linebacker responsibilities (Riley) and all of the tasks of the mike-linebacker (London Fletcher) before he’s trusted to see playing time on defense.

Despite leading the NFL in tackles in 2011, Fletcher is now 37 years-old and entering his 15th NFL season. If Robinson shows well on teams and makes some plays defensively during the preseason, he could give himself a chance to ultimately be viewed as a replacement for Fletcher down the line. For now, though, the 242-pounder will look to stand out among Washington’s backups in his first game-action.

Safety — Tanard Jackson

Jackson began training camp on the physically unable to perform list, sidelined with a calf injury that cost him nearly a week’s worth of practices. Since returning to the active roster Jackson has shown off some of the range and ball-tracking abilities that once helped him to intercept six passes with the Tampa Bay Buccaneers. But the time he lost to his minor calf ailment has positioned him well behind Madieu Williams in a competition to become the Redskins’ starting free safety.

Defensive backs coach Raheem Morris was instrumental in bringing Jackson to Washington. Jackson played the best football of his five-year NFL career when Morris was his positional coach with the Buccaneers. The Redskins are hoping that reuniting the athletic, speedy safety with one of his mentors will garner the type of production that will result in Jackson re-solidifying himself as a starting caliber player.

Jackson has served two suspensions for violating the league’s substance abuse policy. The first time he got suspended Jackson had to sit out the first four games of the 2009 season and the second time he got suspended, in Sep. of 2010, he was forced to miss the final 14 games of the 2010 season and the first six games of the 2011 season.

When he’s been on the field Jackson has been a play-maker. He intercepted passes in each of his first two games after returning to the Bucs last season and posted a 70-tackle five interception campaign in just 12 games in 2009. But the Redskins won’t be giving Jackson multiple chances to prove that he’s a changed man. If he acts like a professional and stays out of trouble, he’s got a chance to climb to the top of Washignton’s free safety depth chart.

Because of the time he missed and the catching up Jackson has to do in the coming couple of weeks, the 27 year-old Silver Spring, Md. native is expected to play a ton tonight.