ESPN wrote:Miami Dolphins running back Ricky Williams has violated the NFL's substance abuse policy for a fourth time and is facing a one-year suspension for the positive drug test, Denver television station KDVR reported on Sunday.
The Miami Herald, citing two sources of its own, confirmed the station's report that Williams had failed the test, but neither media outlet would say which substance Williams used.
An NFL spokesman told ESPN that the NFL had no comment on the report.
Williams has tested positive for marijuana three times and served a four-game suspension when he returned to the NFL last season following a one-year retirement.
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