Rob Jackson missed the first four games of the 2013 season.

The roster exemptions for previously suspended Redskins defensive end Jarvis Jenkins and linebacker Rob Jackson have been lifted, and those two are now a part of the 53-man roster, according to the NFL’s daily transaction report.

Both players last week came off of their four-game suspensions for taking banned substances, and practiced for the first time last Tuesday. Jenkins failed a test for taking a banned performance-enhancing substance. Jackson failed a drug test for what he blamed on a pain killer that wasn’t prescribed to him as he dealt with a bad tooth that he eventually had pulled last season.

The Redskins had applied for — and received — roster exemptions for both so they had time to evaluate each player and his physical conditioning before reinstating them to the 53-man roster.

But the team did go ahead and cut place kicker John Potter and defensive end Phillip Merling despite receiving the roster exemptions. The team didn’t fill those roster spots, so no moves were needed for Jackson and Jenkins’ additions to the roster.

Jenkins would be the starting left defensive end, but it remains to be seen if he will immediately claim his job, or if he will initially play behind Kedric Golston, who had started there the past four games. Jackson would have served as Brian Orakpo’s backup at right outside linebacker. Darryl Tapp had played in that spot in the first four weeks, and rookie Brandon Jenkins has seen time at backup left outside linebacker behind Ryan Kerrigan.

Both players said on Monday that they didn’t know what the coaches had planned for them. But they worked primarily on the scout team initially.

Have a Redskins question? E-mail Mike Jones at with the subject line “Mailbag question” for him to answer it in The Mailbag on Tuesday.

What’s ahead:

● Mike Jones’s mailbag, Mark Maske’s top-10 ranking and an Outsider post.

More on the Redskins and NFL:

Tribe pushes for franchise name change as NFL owners gather

Wise: Never may be sooner than anyone thought

Milbank: What’s in a name for Redskins? Plenty. 

Redskins return to work with ‘sense of urgency’

At a crossroads under Shanahan: Will the real Redskins please stand up?

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