Allen did not record any tackles during Sunday's 16-13 win over Cincinnati.
After spending most of the season on the practice squad, Allen was promoted when Nat Behre (pectoral) was placed on injured reserve in October. Allen finished the 2018 season with one tackle in six games, playing exclusively on special teams. He has one year remaining on his current contract.
Allen was promoted to Pittsburgh's 53-man roster from the practice squad Tuesday.
A fifth-round pick in the 2017 NFL Draft, Allen appeared in 10 regular season games last season for the Steelers and recorded two special teams tackles. He found himself on the practice squad for the first four weeks this season, but received promotion after Nat Berhe (pectoral) was placed on injured reserve Tuesday. Allen will look to provide depth in the secondary for Pittsburgh.