go with Ricky Williams for sure. He's playing a week team, and Ronnie Brown is probably not going to play. Heres a link
2 Miami Dolphins RB Ricky Williams is expected to start in Week 16 in place of RB Ronnie Brown (ankle/knee). KFFL
Dec 22 Brown has yet to practice with the Miami Dolphins this week, decreasing his chances of playing in Saturday's matchup with the Tennessee Titans. The rookie running back, who officially is listed as questionable on the injury report, is nursing a sore left knee and ankle. He will be a game-time decision.
Advice: Ricky Williams will handle the bulk of the rushing load if Brown is unable to take the field this weekend. In 14 games this season, Brown has 886 yards and four touchdowns on 199 carries, along with 30 catches for 219 yards and a score. He's lost four fumbles.