The NFL suspended defensive end Greg Hardy for 10 games without pay Wednesday for conduct detrimental to the league after concluding there was ''credible evidence'' he roughed up his former girlfriend nearly a year ago when he was a member of the Carolina Panthers. Hardy, who joined the Dallas Cowboys as a free agent on a one-year, incentive-laden deal, was notified Wednesday of the decision in a letter from Commissioner Roger Goodell. Goodell cited ''sufficient credible evidence that Hardy engaged in conduct that violated NFL policies in multiple respects and with aggravating circumstances.'' His assault case had been dismissed in a North Carolina court because his accuser refused to cooperate with prosecutors, but an NFL investigation concluded that Hardy used physical force against Nicole Holder in at least four instances. ''The use of physical force under the circumstances present here, against a woman substantially smaller than you and in the presence of powerful, military-style assault weapons, constitutes a significant act of violence in violation of the personal conduct policy.'' The 26-year-old Hardy was on the commissioner's Exempt List last season and did not play for Carolina, although he was paid his $13.1 million salary.