Sweed was placed on injured reserve Monday with a non-football related illness. Coach Mike Tomlin would not reveal any details of Sweed’s problem Tuesday.
Galloway was cut by New England earlier this season.
The Steelers also signed long snapper Jared Retkofsky to replace Greg Warren, who injured a right knee ligament on the final play of Pittsburgh’s win over Green Bay. Retkofsky was the Steelers’ long snapper for the final two months and the playoffs last season after Warren tore a knee ligament.
Retkofsky had been playing for the New York Sentinels of the United Football League.