The Raiders are off today and Sunday, but general manager Reggie McKenzie is apparently still hard at work, juggling his 53-man roster.

The Raiders claimed former Redskins T Willie Smith ex-Eagle LB Keenan Clayton and former Seahawks CB Phillip Adams off waivers.

To make room for them on their 53-man roster, the Raiders waived CBs Chimdi Chekwa and Bryan McCann and waived/injured DT Jamie Cumbie.  

Smith made the Redskins’ roster last year as an undrafted rookie from East Carolina. He started the final three games at left tackle, facing three of the NFL’s top pass rushers: Jason Pierre-Paul, Jarred Allen and Trent Cole, who combined for 49.5 sacks last year. Each of the three had one sack in those matchups, although Pierre-Paul’s didn’t come against Smith.

The Eagles drafted Clayton in the fourth round in 2010 out of Oklahoma. He appeared in 21 games with one start for Philadelphia and played primarily on special teams.

The Raiders kept five linebackers on their initial 53-man roster and just one weak-side linebacker, rookie Miles Burris. Veteran weak-side linebacker Aaron Curry, who was expected to start, was placed on the PUP list with injuries to both knees and will not be eligible to return until after the first six weeks of the season. The Raiders needed to add depth at the position, and their struggling special teams needed a boost, too.

The Raiders kept only one backup tackle on their initial 53-man roster, second-year man Joe Barksdale. He was expected to challenge right tackle Khalif Barnes for the starting job but never did.

Adams was drafted by San Francisco in the seventh round out of South Carolina State in 2010. He played 15 games for the 49ers that season. Last year he played five games for New England and one for Seattle. He has one career interception and zero starts.

Chekwa, a fourth-round pick out of Ohio State last year, appeared in only four games in an injury-plagued rookie season. He has struggled throughout much of training camp. McCann was a surprising survivor in the final cut Friday. But with seven cornerbacks on the initial 53-man roster, something had to give.

Cumbie, who spent last sdason on the practice squad, had an impressive camp but was slowed by a foot injury.

In other moves, the Raiders announced they have signed four players to their practice squad: LBs Kaelin Burnett and Nathan Stupar and WRs Brandon Carswell and Tray Session. All four rookies were cut Friday.

The Raiders drafted Stupar in the seventh round out of Penn State. Of the Raiders’ six draft picks, he was the only one who didn’t make the 53-man roster, but he showed some promise in the preseason finale at Seattle, making 11 tackles with one sack.

The Raiders have four spots left to fill on their practice squad.

Follow Raiders reporter Eric Gilmore on Twitter: @CBSSportsNFLOAK.