Terms of the deals were not disclosed.
In addition, the team placed running back
He has spent the first 14 weeks of the 2013 season on the team’s practice squad.
Jamison played collegiately at Rutgers from 2010-12, appearing in 25 games with 20 starts.
For his career, he compiled 1,972 rushing yards on 486 carries with 13 rushing touchdowns.
In 2012, he was named second-team All-Big East after rushing for 1,075 yards on 255 carries (4.22 avg.) with four touchdowns, becoming only the seventh player in school history to rush for more than 1,000 yards in a season.
Jamison, 22, attended The Bolles School in Jacksonville, Fla., where he helped his team win back-to-back Florida Class 2A state championships in 2008 and 2009.
He was born on Nov. 23, 1991.
Maysonet (5-10, 210) originally signed with the Philadelphia Eagles as a college free agent on April 29, 2013.
He was waived by the Eagles on May 20 and acquired on waivers by the Cleveland Browns on May 21.
After being waived by the Browns on Aug. 30, he signed to the Indianapolis Colts’ practice squad on Sept. 16. He was released by the Colts on Sept. 26 and signed to the San Diego Chargers’ practice squad on Oct. 2 before being released on Oct. 9.
He signed to the New York Jets’ practice squad on Oct. 15 and was released by the Jets on Oct. 22.
Maysonet, who will turn 24 on Friday, played collegiately at Stony Brook, where he rushed for 4,725 yards on 695 carries (6.8 avg.) with 48 touchdowns from 2010-12.
He began his college career at Hofstra before transferring following the university’s decision to terminate its football program.
Maysonet attended Riverhead (N.Y.) H.S. He was born on Dec. 13, 1989 in Bayamon, Puerto Rico.
Royster (6-1, 216) appeared in 10 games this season for the Redskins, serving primarily in a special teams capacity.
He has played in 32 games with two starts in his three seasons in Washington.