Briggs (6-foot-4, 230 pounds), who was originally signed to Denver's practice squad on Sept. 22, is a second-year player who spent parts of the 2009 and '10 seasons on San Francisco's active roster. He played in four games with the 49ers last year and totaled four special-teams tackles. He also played in the club's opener against Seattle this season.
Briggs originally signed with San Francisco as a college free agent on April 30, 2009, from Bowling Green State University, where he was a two-time All-Mid-American Conference selection and the 2006 MAC Player of the Year.
A two-time all-league choice at Mt. Healthy High School in Cincinnati, he was born on Oct. 31, 1985. His first name is pronounced DIE-rell.
Riley (6-foot-3, 205 pounds), is a first-year player who spent time on Carolina's practice squad this season. He spent the entire 2009 season on Baltimore's practice squad after signing with the club as a college free agent from Duke University.
He was a two-time second-team All-Atlantic Coast Conference selection with the Blue devils, as he finished his career with 144 receptions for 2,413 yards with 22 touchdowns.
Named All-Greater Savannah Area Offensive Player of the Year after his senior season at Windsor Forrest High School in Savannah, Ga., Riley was born on Aug. 5, 1987.