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For one-time workhorse Larry Johnson, the handoffs stopped coming nearly a year ago. He says he learned his lesson waiting for another chance to carry the ball.

Johnson signed Tuesday with the Miami Dolphins and knows he must quickly make a good impression, including off the field, where repeated missteps derailed his career.

"It's kind of hard to convince anybody with my colorful background that, yeah, I've changed," said Johnson. "But you change with every situation you go through. You know that you can't get many more shots. You do the best you can with your opportunity and ride on out to the sunset."

Johnson sat out most of 2010 after being released by the Washington Redskins last September. He twice made the Pro Bowl and has career rushing totals of 6,221 yards and 55 scores, but his most recent touchdown came in 2008.

He was drafted in the first round by Kansas City in 2003, and his time there was marred by off-field problems, including two suspensions in his final 12 months with the team. The Chiefs released him in 2009 after he posted a gay slur on his Twitter account and questioned the competence of coach Todd Haley.

Johnson cited his background as the reason he remained out of work this summer until almost four weeks into training camp.

"I don't think it had anything to do with talent," he said. "I understand you want your best guys to represent the organization. You go with the guy with the cleaner slate. That's what I realized going through this process. All you can do is be thankful for one little shot."

Miami coach Tony Sparano made the acquisition of Johnson sound very much like a tryout. Sparano said conversations with Johnson convinced the Dolphins he was worth the risk.

"I think he's at a different place in his career," Sparano said. "It's no secret — I don't think there are many more opportunities. The guy has a chance to make an impression, and hopefully he uses that to the best of his ability."

With the addition of Johnson, the Dolphins hope to upgrade their depth behind Reggie Bush and rookie Daniel Thomas. The team waived running back Kory Sheets, who missed all of last season with an Achilles tendon injury.

Before signing Johnson, Miami worked out at least two other veterans, Tiki Barber and Clinton Portis. When asked why the Dolphins added Johnson after declining to re-sign Ronnie Brown or Ricky Williams, Sparano said: "This is a different role totally. ... I'm not asking him to be anything more than he is. I'm not asking him to be the man. I just want him to come in and be a piece on this team."

Johnson, who lives in nearby Miami Springs, said he has only been hurt once in his career and feels fresh at age 31.

"It's a great opportunity to get my career back on track," he said. "Obviously I have to impress the coaches. I have two preseason games. Hopefully if I impress them enough, I can find a role."

Johnson's best years were 2005-06 with the Chiefs, when he had consecutive 1,750-yard seasons and ran for a total of 37 touchdowns.

After they released him in November 2009, he played in seven games as a reserve in Cincinnati. He signed a three-year, incentive-laden contract with Washington in March 2010, but gained only 2 yards on five carries in two games before being cut by the Redskins.