The Dolphins have signed Ricky Williams to a one-year contract extension that will keep him in the Miami backfield through 2009, a source close to the veteran running back said.

Williams

The source, speaking on condition of anonymity, told ESPN's Chris Mortensen on Saturday that there was no signing bonus, but Williams' salary in 2009 could increase significantly over this year's base of $730,000.

The Miami tailback can increase his 2008 compensation with easily achievable incentives, the source said. Williams, 31, was scheduled to be a free agent in '09.

Dolphins officials had no comment on Williams' new pact.

Williams, the 2002 NFL rushing champion, has played in only 13 games since retiring in the summer of 2004. He has tested positive for marijuana at least four times since the Dolphins acquired him in 2002, and their franchise-record playoff drought began that same year.

In July, the 1998 Heisman Trophy winner said he felt good going into the Dolphins' season.

The Dolphins, coming off an embarrassing 1-15 season, are banking that he does.

Williams returned last year, but his comeback lasted less than one half. He gained only 15 yards on six carries before he fumbled, was stepped on and tore his chest muscle against Pittsburgh. Teamed with Ronnie Brown, who was on pace for a career season in 2007 before he tore a ligament in his right knee, Miami's running backs have lofty expectations.