The team announced the moves on Friday.
Omameh, who spent the past two seasons in Jacksonville, has played in 53 regular-season games with 44 starts for Tampa Bay, Chicago and the Jaguars. Last season, the former Michigan product started 16 games at left guard for Jacksonville.
Riley played in 11 games the previous two seasons for Tennessee. He had 11 tackles, an interception, and one special teams tackle in seven games last season. He was signed as an undrafted free agent by Tennessee on 2015.
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