If Onobun clears waivers, he will revert to Jacksonville's injured reserve. He hurt his knee in practice earlier this week.
The 5-foot-11, 240-pound Kettani was originally signed as a rookie free agent by New England in 2009. He left training camp that year for military commitments. He was reinstated to New England's roster in September 2011 and spent part of that season on the club's practice squad. He spent the entire 2012 season on Washington's practice squad and was with Kansas City for the 2014 offseason before being waived in May.
He ran for 2,091 yards and 15 touchdowns in four seasons at Navy.