DAVIE, Fla. - Life after Ricky Williams has begun much earlier for the Miami Dolphins than they anticipated, in large part because they overused him, his agent said Monday.

Williams, the Dolphins' standout running back, did not want to end his career by limping out of the NFL after eight years the way Earl Campbell did, so he decided to retire at age 27, the agent, Leigh Steinberg, said. Campbell, an NFL Hall of Famer, is Williams' role model and a fellow former University of Texas running back.

"There was a lot of frustration about the battering ram nature of it," Steinberg said from his office in Newport Beach, Calif. "In so many of his carries, he was running straight into the line. It took a heavy physical toll. Maybe it took an emotional toll."

Williams averaged 271 carries a year in three seasons with New Orleans, but he became the overriding focus of the Dolphins' offense as soon as he was traded to Miami before the 2002 season. He led the NFL in carries in both of his seasons in Miami - 383 in 2002, when he topped the league in rushing, and 392 last season.

Though Steinberg emphasized that Williams was in the best condition of his career, he said it gave him pause to think that he had carried the ball 775 times over two seasons. That is more carries than many backs have in a career.

"The act of running a football into the waiting arms of 300-pound defensive tackles whose goal is to fling one to the turf time after time requires an extraordinary degree of passion and commitment," Steinberg said. "And he found it lacking."

Dolphins coach Dave Wannstedt maintains that his objective is to strike a balance between running and passing. Yet with quarterback Jay Fiedler limited in his throwing range and sometimes slowed by injuries, and with a lack of depth at wide receiver, much of the offensive burden fell to Williams.

By losing Williams, the Dolphins are in position to buy another top player but the timing could not be worse. They will save his $3.6 million salary against the salary cap. But with training camps scheduled to open this week, teams are preparing for the season, not looking to dump a franchise runner.

Williams' late announcement kept the Dolphins from having a shot at signing running back Eddie George, who was acquired by Dallas two days after Tennessee released him. The Dolphins have mulled the idea of picking up either James Stewart or Stacey Mack, two unemployed former starters, but they have apparently decided to wait.

They plan to start training camp on Friday with Williams' backup, Travis Minor, as the starter. Minor averaged 4.7 yards a carry last season in 193 attempts. Sammy Morris, a fullback who came from Buffalo, might also get a serious look.

Rick Spielman, the Dolphins' general manager, sounds as if he is inclined to wait until August before deciding whether to take a drastic measure, like a trade. That would give him time to both determine if Minor or Morris can replace Williams and scrutinize the running backs who might be cut.

"We've got a 65- and a 53-man cut coming up, so you don't know what's going to happen and what players might become available down the road," Spielman said this week.

Wannstedt said that even without Williams the remaining Dolphins are a formidable team.

"We have quality players at every position, with a very good attitude, that have worked extremely hard," Wannstedt said Sunday after Williams announced his retirement. "And our goals haven't changed. I really don't need to tell them that. They'll be telling me."

In the meantime, Steinberg said Williams was at peace with his decision, eager to travel, read, return to school and pursue photography as a hobby, for starters. But he said Williams would be tempted at some stage to return to the game.

"This is my 30th year of representing football players, and I haven't seen a player leave the game in any capacity and not have the desire to come back," Steinberg said. "So there's no question that at some point, whether he knows it or not, he'll certainly have pangs."