David Montgomery, running back for the Detroit Lions, is expected to miss some time due to a rib injury. Montgomery suffered the injury in Sunday's win over the Buccaneers. It is advised to plan on him missing at least Week 7's game against the Baltimore Ravens. With Montgomery out, Craig Reynolds is expected to be a popular waiver option. However, fantasy managers should be cautious as the Ravens have a strong defense, ranking second in overall DVOA and seventh against the run. Rookie Jahmyr Gibbs is also expected to return from injury soon.