Hubbard appeared in eight games this season with the Steelers. He initially made the team in 2014 after spending the 2013 season on the practice squad.
Nix caught two passes for 16 yards while serving mostly as a blocking back and on special teams during his rookie season in 2015. He went on injured reserve last month after injuring his right foot in a loss to Baltimore on Dec. 27.
The Steelers also signed 10 players to futures contracts: safety Jordan Dangerfield, offensive linemen Matt Feiler and B.J Finney, cornerback Isaiah Frey, tight end Xavier Grimble, defensive end Caushaud Lyons, running backs Rajion Neal and Abou Toure, wide receiver Shakim Phillips and safety Ray Vinopal.
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