With the NFL playoffs still going on, teams can sign players to contracts, but they can be their own free agents or those that were not on any team active roster at the end of the season. The Arizona Cardinals have been active, having signed 10 players to "futures" contracts for 2012.
On Saturday, the team announced the signing of Williams and also that of another receiver that was with the team in 2011 -- Jaymar Johnson.
Johnson spent much of the season with the Cardinals on the practice squad, but was promoted to the active roster at the end of November. He played one snap on offense for the season and did not catch a pass.
He is, though, quite fast and friends with Larry Fitzgerald.
That is now 11 players the team has signed to futures contracts. Again, these are typically young players that only come to camp before getting cut, end up on the practice squad or make the active roster at the end of the depth chart. It is part of the process of developing young players.
Adding Williams and Johnson gives Arizona a large crop of young receivers. We will see if any of them can become contributors.