Washington Redskins defensive coordinator Jim Haslett came away from his early offseason evaluation of his unit encouraged, thanks to the development he saw in his front seven. But the coach believes the Redskins’ defense must shore things up in their secondary if they expect to take another step forward.

Haslett, speaking after Thursday’s practice leading up to Saturday’s Senior Bowl, thinks the collection of defensive linemen and linebackers can rival that of any of the top groups in the NFL.

“Obviously we want to get better in every area, but we think the front is about as good as it gets. We’re excited about that,” said Haslett, whose unit went from 31st in total defense in 2010 to 13th in 2011. “We’ll be getting [2011 second-round defensive end] Jarvis [Jenkins] back. But we need to get some stability on the back end. … We’re not done rebuilding and we’re not done doing the things we want to do on defense. We’ve got to get some stability on the back end.”

On the corners, the Redskins have DeAngelo Hall (who is capable of making game-changing plays, but also known for giving up the big play) and Josh Wilson (whom coaches believe developed into a solid cover man as he became more comfortable later in the season). But Haslett and head coach Mike Shanahan believe both can improve under the direction of new defensive backs coach Raheem Morris.

And the team still needs a reliable nickel back. Kevin Barnes and Byron Westbrook both saw time at that position, but neither played at a high level consistently, coaches say.

The safety position faces even more uncertainty.

Strong safety LaRon Landry will be a free agent and for a second straight year ended the season on injured reserve because of a bad Achilles’ tendon that he has yet to have operated on although specialists have told him he needs to do so.

And free safety Oshiomogho Atogwe, whom the team signed last offseason, was hobbled by knee, hamstring and toe injuries much of the year, and Haslett said he doesn’t know what kind of recovery he will make.

Rookie DeJon Gomes and veteran Reed Doughty both played a significant amount, but neither are on the same level as a healthy Landry and Atogwet.

So, in the coming weeks, as the Redskins approach free agency and the draft, the decision must be made on both starting safety positions.

“They’re interchangeable, so strong, free, doesn’t make a difference, but we’ve got to get some guys back there that we can rely on, that can create some turnovers and do the things we need them to do,” Haslett said. “We’ll have to see the next couple months [how Atogwe recovers]. … I’m not worried about LaRon. I don’t know what the situation was or why the decision was made not to have [surgery] or to have it, so I’m not really sure. Right now, I’m just having fun with these guys, enjoying it and when we get back to work, we’ll figure out what we need to do.”