Offensive lineman Justin Murray signed a futures contract with the Browns in January, but he won't be continuing to try to make the team.
The Dolphins made an addition to their defense and special teams on Wednesday.
Despite using five different starting quarterbacks and signing a 38-year-old Joe Flacco off the couch in November, the Browns still went 11-6 to reach the playoffs last season, where Cleveland's league-best defense gave up 45 points in a blowout lost against the Texans in the Wild Card.
The Steelers went 10-7 last season before losing to the Bills in the Wild Card.