Here's the press release from the Bengals on Tuesday: 

The Bengals signed free agent WR Doug Gabriel to a one-year contract.
 
Gabriel (6-2, 215; Central Florida) is a fifth-year NFL player in 2008. He has played in 57 games with 12 starts and has 101 career receptions for 1550 yards and eight touchdowns. He also has 86 career kickoff returns for a 21.5-yard avg., with one TD.
 
He was a fifth-round draft choice of Oakland in 2003 and played for the Raiders through 2005. He was traded to New England just before the start of the 2006 season and played for the Patriots before being reacquired by Oakland on waivers in December of that year., He was released by the Raiders on Aug. 27, 2007 and was not with an NFL team during the '07 season.