Vickerson was injured in the Broncos' loss at New England Sunday night. He's the second Denver defensive starter to get hurt this month, joining safety Rahim Moore (leg), who was put on recallable IR.
Vickerson was in the midst of a solid season, helping Denver rank fourth against the run and collecting 22 tackles and one sack, which came against Tom Brady in the first quarter Sunday night before he got hurt.
Fua is a third-year pro who played in 27 games, including a dozen starts for Carolina, over the last three seasons. He was waived by the Panthers Nov. 12.