Rookie cornerback Darrent Williams, who has started nine games for the Denver Broncos and established himself as one of the top first-year defenders in the league, could miss the balance of the season with a groin injury sustained in Sunday's win over the Ravens. The second-round pick underwent an MRI examination Monday for what was diagnosed as a strained right groin and, while results were not yet available, it is believed Williams has at least a small tear. A source close to Williams said he will miss at least two weeks and could be sidelined substantially longer, perhaps for six weeks. Under that worst-case scenario, Williams, who has lent stability and playmaker skills at the right cornerback spot and teamed with veteran Champ Bailey to provide Denver an excellent coverage tandem, would not return until around the time of the AFC title game. Fellow rookie Domonique Foxworth, a third-round choice who has logged considerable playing time, will replace Williams at right cornerback.