Montgomery (ankle) didn't practice Monday, Zack Cox of NESN.com reports.
Montgomery sustained a right ankle injury during Friday's preseason game versus the Raiders, and there has yet to be a concrete update on the severity of his injury since then. The 29-year-old had been projected to help fill the change-of-pace/pass-catching void created by the retirement of James White, but if he's forced to miss time early on this season, rookie Pierre Strong is a candidate to see increased opportunities in New England's offense, while the team's top early-down options Damien Harris and Rhamondre Stevenson also could see added looks in the passing game in that context.