Because Ted Ginn Jr. is only 25, the 49ers believe he can still blossom into a reliable deep-threat receiver.

Even if he doesn't, Ginn's special-teams ability fills a major need a week before the NFL draft. The 49ers acquired the former Ohio State standout Friday by trading their fifth-round pick (145th overall) to Miami Dolphins.

"He's a bundle of potential, and his upside is off the charts," 49ers coach Mike Singletary said. "This guy can fly."

The Dolphins thought the same thing about Ginn when they drafted him ninth overall in 2007. But he averaged only 34.7 receiving yards per game and contributed just five receiving touchdowns over three seasons.

Miami began shopping him shortly after acquiring receiver Brandon Marshall from the Denver Broncos this week.

The 49ers pounced. The trade represents the first big move by Trent Baalke, the director of player personnel who took over in the wake of general manager Scot McCloughan's exit.

Baalke recognized that the 49ers had one of the NFL's worst return games last season. There was speculation that they would find a return man next week — with Clemson running back C.J. Spiller often linked to the team in mock drafts — but Ginn is a proven commodity who ranked among the AFC kickoff return leaders in 2009.

Against the New York Jets last season, Ginn scored on kickoff returns of 100 and 101 yards in the same quarter. That made him the first player with two 100-yard kickoff returns in a game.

"Ted gives our coaching staff another quality player to utilize on game day," Baalke said Friday.

Ginn averaged 24.9 yards per kickoff return in 2009, including that career-best 101-yarder.

Earlier in his career, he showed promise as a punt returner — he took one back 87 yards for a touchdown as a rookie — but handled those chores only five times last season.

Ginn said Friday that he would love to do whatever special teams jobs the 49ers have in mind.

"I'm very open. That's one of the things that I like to do," he said. "As far as kickoffs and punt returns, that's me. I just feel that's another way that I can get the ball in my hands and make plays for my team."

Ginn said he had a brief conversation with Singletary early Friday, but the two did not discuss the receiver's role for 2010. Ginn is believed to be competing for a third-receiver spot behind starters Michael Crabtree and Josh Morgan.

Ginn believes he can still carve an even bigger niche as a go-to receiver. He led Ohio State in receiving during his final season of 2006 (59 catches, 781 yards and nine touchdowns). A year earlier, he became the first player in school history to score a touchdown receiving, rushing, returning a kickoff and returning a punt in the same season.

"We haven't really talked about depth charts, or playing time or anything like that," Ginn said of the 49ers. "They are welcoming me with open arms, and I'm going to come in and just compete and be the player that I am. Let my play talk for itself."

Ginn acknowledged the pressure that comes with being a high draft pick. He said people expect a first-rounder to contribute right away, when in reality it can take some players three years or more to adjust to the NFL.

That's why he's eager for another beginning.

"I wouldn't say a sense of relief, but it's always good to have a new start," Ginn said. "Coming out to the 49ers gives me a brand new start. Leaving Miami, I don't hold any grudges, no bad feelings about anything. My time was up there. I enjoyed it there, and now it's time to move on."