The Steelers picked linebacker Thaddeus Gibson in the fourth round of the 2010 draft. During his rookie season, Gibson was cut by the Steelers.
He landed with the 49ers, appearing in two games. And he was recently waived by the Niners.
Of all teams, the Steelers put in a claim for him.
PFT has confirmed that the Steelers, Bears, and Redskins made claims for Gibson. (The transaction, as best we can tell, was first reported by Scout.com.) Since the Redskins had the worst 2010 record of the three teams, the Redskins secured his contract.
Given that the Steelers played in the Super Bowl, they have waiver priority over only one team — the Packers.