Miami is searching for depth behind starting running back Lamar Miller, who rushed for a career-high 1,099 yards and eight touchdowns last season. Power tailback Knowshon Moreno is an unrestricted free agent coming off a season-ending knee injury and is not expected to return.
Ridley spent his entire career with the New England Patriots and gained 340 rushing yards in 2014. He had some high moments but also developed a reputation for fumbling at bad times.
The Dolphins want to see if Ridley and Miller would make a good pairing in Miami, while also keeping an eye on tailback prospects in the draft.