While the Miami Dolphins were desperately seeking help at tailback, two days after being informed by Ricky Williams that he would retire, Williams's agent said yesterday that the running back's abrupt departure from the sport could be followed by an abrupt return at some point.

"Playing football -- and, especially, playing running back -- is not a job for the weak of heart or the unmotivated," Leigh Steinberg said by telephone. "For whatever reason, he's just lost his motivation. Whether it's temporary or permanent remains to be seen. . . . The timing was unfortunate. It's not contractual. It's Ricky. He's an American original."

Williams, 27, has rushed for 6,354 yards in five seasons since the New Orleans Saints traded eight draft choices to the Washington Redskins in 1999 for the right to select the Heisman Trophy winner out of the University of Texas with the fifth overall pick. He has run for 3,225 yards in two seasons since the Dolphins obtained him in a trade with New Orleans that ultimately cost Miami two first-round draft picks, and he potentially is walking away from a contract that would pay him salaries of $3.7 million in each of the next two seasons and $3.5 million in 2006.

Dolphins Coach Dave Wannstedt said during an afternoon news conference he had been "totally surprised" by Williams's decision, and added: "My main thought process was to try to get Ricky to come back here to talk about this thing and try to get this thing back on track. He obviously chose to go another direction. . . . If he's going to change his mind, anything like that, it would have to be initiated on his part. . . . He made his decision. He's got his reasons. Things happen, and you move forward.

"This is a game of passion. It takes a lot of time and a lot of commitment. For whatever reasons, he doesn't feel like he can make that commitment. I'm not going to judge."

Williams is on a trip to Japan but is scheduled to return to the Miami area in a few days. He informed Wannstedt of his retirement plans Friday and told the Miami Herald in a telephone interview Saturday that he would not change his mind.

The team was left with little chance to find a suitable replacement, with the last of the proven free agent tailbacks, Eddie George and Antowain Smith, having signed elsewhere last week. The Dolphins' options include free agents James Stewart, Trung Canidate and Stacey Mack. Canidate is considering undergoing foot surgery after his unsuccessful 2003 season with the Redskins.

The club could attempt to trade for an established tailback and could offer defensive end Adewale Ogunleye, the reigning AFC sack champion who has been in a contract dispute with the team and has said he won't report to training camp unless he receives a new, long-term deal. Or the Dolphins simply could turn to Williams's backup, Travis Minor, to be their featured runner in a season in which Wannstedt's job probably is on the line. In three NFL seasons, Minor has totaled 654 rushing yards.

The Dolphins' veteran players are scheduled to report to training camp Friday. The club could attempt to sue Williams to recover a prorated portion of his signing bonus for failing to fulfill the terms of his contract -- the approach that the Detroit Lions took when Barry Sanders abruptly left the sport. The Lions managed to force Sanders to repay some of the bonus money, but their tactics further inflamed the tense situation and Sanders resisted the team's repeated efforts to lure him back.