The 33-year-old point guard cleared waivers at 6 p.m. Thursday, and the Heat announced the signing about an hour later. Alston will be with the team when it opens a six-game road trip Friday in Phoenix.
Alston, who started all 23 playoff games with Orlando last season when the Magic reached the NBA finals, played with the Heat in 2003-04 -- Wade's rookie season. Alston's contract with the New Jersey Nets was bought out Tuesday, and he made it clear right away that Miami was atop his list of teams to join.
"I just met with him and he said he's in great shape," Heat coach Erik Spoelstra said by telephone from Phoenix Thursday night. "He's a worker. We're excited about it. We always felt Rafer was a Miami Heat player. ... But more than anything, the fact that his game fits our philosophy and that he's been with us before and buys into it and loved his time here and wanted to be here, it made it a great fit."
Alston, who has been an outstanding on-the-ball defender, could play Friday against the Suns. Spoelstra hasn't made a final decision.
Alston started 13 of New Jersey's first 15 games this season -- part of the Nets' abysmal 0-18 start. He's shooting only 34 percent this season, well below his career average of 38.5 percent, and was averaging only 9.7 points.
A change of scenery could do him wonders.
"We are thrilled to have Skip back in a Heat uniform, as he brings another set of skills and experience to the point guard position," Heat president Pat Riley said in a statement. "From his time in Miami, we know both his game and him as a person, and we had a great experience with him in the past. We are very happy to have Skip back in the Heat family."
The signing comes at a crucial point of Miami's season. No team played fewer road games in the season's first 72 days than Miami, which is 11-10 at home, but just 6-6 on the road and sitting in fifth place in the East.
The Heat are about to start making up for all those early home dates.
On Friday, they begin a stretch where 20 of their next 27 games will be on the road, no homestand of longer than two games until the first week of March.
"We just have to continue to grow as a team and continue to learn from our mistakes," Wade said.
Adding another veteran won't hurt in that regard.
The Heat had only two point guards on the roster after trading Chris Quinn on Tuesday to New Jersey -- a deal the Nets made almost at the same time they were buying out Alston's contract.
Alston helped Miami close the 2003-04 season with 17 wins in its final 21 games, getting the Heat the No. 4 seed in the Eastern Conference that year, and becoming a close friend and adviser to Wade along the way.
"Veteran guys are so important in this league," Wade said. "They've done it for so long and Skip became a leader. He's a general on the floor, really helps to lead his team."
Spoelstra said it won't take Alston long to get up to speed, especially since Miami's defensive system is "similar enough" to what he knew with the Heat.
Miami now has an unusual situation at the point, with three players at the position who have all started at least 11 games this season. Carlos Arroyo took over Miami's starting job in mid-December from Mario Chalmers, who started every game last year as a rookie for the Heat.
"It's definitely a positive for us at one of the most important positions on the floor," Spoelstra said. "Now we have great depth and all three of them are very professional. Does that mean it's going to be easy? No, probably not for whomever is going to be the third guard. But I think everybody's heart is in the right place. We'll see how it plays out."