Smith, released Sunday by Tampa Bay, joined the Dolphins for Wednesday's practice. He made the Pro Bowl with the Buccaneers as a rookie in 2008, when he averaged 27.6 yards on kickoff returns and 14.1 on punt returns.
Smith led the NFL in kickoff returns in 2009 with an average of 29.1 yards. But he was slowed by injuries last year and during the Bucs' recent training camp.
The Dolphins have been seeking a replacement for returner Ted Ginn Jr., traded in April to San Francisco.
To make room on the roster for Smith, Miami waived offensive lineman Joe Reitz.
Also Wednesday, Pro Bowl tackle Jake Long returned to practice on a limited basis.
Long, nursing a left knee injury, was involved in some of Wednesday's workout. Linebacker Channing Crowder, who has been sidelined since Aug. 17 because of a groin injury, jogged on the side.
Meanwhile, a change in hierarchy announced Tuesday left Jeff Ireland in control as general manager, while Bill Parcells remains as a daily consultant. Safety Yeremiah Bell said the timing was odd, with the move being disclosed the week of the season opener at Buffalo, but coach Tony Sparano said he doesn't consider the matter a distraction.
"It's not something that's a surprise," Sparano said. "The first day I got here, I knew eventually this day would come. It's business as usual. The guy I speak to several times a day is Jeff Ireland. For me it doesn't change anything."
The Dolphins said the change was part of a long-range plan when the Parcells regime took over at the end of the 2007 season and hired Ireland shortly thereafter. The regime -- including Sparano -- took over a team coming off a 1-15 season and took it to the playoffs in 2008.
Bell viewed a reduced role for Parcells as a setback.
"It is unsettling, because he's the guy who turned us around from 1-15," Bell said. "He brought in all the players to turn this thing around, and with him being gone, we're definitely going to feel it."
The Dolphins open the season Sunday at Buffalo.
Information from The Associated Press was used in this report.