Retired Dolphins running back Ricky Williams said he failed a third drug test for marijuana use, which would cost him a four-game suspension if he decides to come back to the NFL.

Williams told the Miami Herald that marijuana played a larger role in his retirement than he indicated when he walked away after five pro seasons. He said he learned of the failed test and possible suspension days before telling Coach Dave Wannstedt last week that he was through playing.

Williams said, however, that there were "a hundred reasons" for his retirement and that his desire to continue smoking marijuana was only one of them.

"I didn't quit football because I failed a drug test," said Williams. "I failed a drug test because I was ready to quit football."

Wannstedt said the Dolphins have received no notification from the NFL regarding a third failed drug test, and Williams's latest revelation caught them by surprise.

"We knew nothing about it," Wannstedt said. "I'm totally surprised and shocked again."

Dolphins spokesman Neal Gulkis and NFL spokesman Greg Aiello declined to comment yesterday.

In May, three South Florida newspapers quoted unidentified sources saying Williams tested positive for marijuana and faced a fine of at least $650,000 for violating the substance-abuse policy for the second time since joining the Dolphins in 2002.

* JETS: Chad Pennington plans to make the first opening day start of his career in September -- with or without a new contract. Pennington's agent, Tom Condon, and New York are negotiating a new deal, but the quarterback has told Condon if a deal isn't reached by Aug. 31, then talks will be shelved until after the season.

"I've made sure it won't be a distraction. That's why I've allowed them to discuss it through August, but after that there are no discussions," Pennington said as the Jets reported for training camp. "As far as I'm concerned, after today I'm not talking about it."

Pennington is entering the last year of a five-year deal that will pay him a base salary of $4.57 million.

* BEARS: Lance Briggs, who started 13 games at outside linebacker last season, moved to the middle as the temporary replacement for Pro Bowl linebacker Brian Urlacher.

Urlacher pulled a hamstring Wednesday and is expected to be out several weeks.

Coach Lovie Smith said second-year player Hunter Hillenmeyer and rookie Jeremy Cain also would get a chance to fill in for Urlacher.

Briggs, a second-year player from Arizona, played middle linebacker in college but not as a rookie.