Lewis, who played two years at Arizona State, was signed by Tennessee as an undrafted free agent in 2011. He appeared in eight games in 2012, five with Tampa Bay and three with Dallas. He was cut by New England at the end of training camp last season.
Whitley has been on the practice squads of Philadelphia, San Francisco and Dallas since being signed by the Cowboys as an undrafted free agent in 2012. He spent two weeks on the New Orleans practice squad during the playoffs last season.