Cutting wide receiver Anthony Armstrong and reworking the contract of backup quarterback Kyle Orton Wednesday allowed the Cowboys to free up the approximately $1 million needed to sign Allen (one-year deal) and linebacker Justin Durant (two-year deal). Armstrong didn't have a reception for the Cowboys last season.
Allen started just seven games for the Steelers in the last three seasons. He previously played six seasons for the Buccaneers.
The Cowboys hosted free agent safety Michael Huff Monday, but he agreed to terms on a three-year, $6 million contract with the Ravens on Wednesday.
Durant, who started 26 games for the Lions in the last seasons, is expected to compete with Kyle Wilber at outside linebacker. He confirmed his move to Dallas via Twitter: