Northampton scrum-half Alex Mitchell could miss England's Autumn internationals after Saints director of rugby Phil Dowson said there was "no timeline" on his recovery from a neck injury.

Mitchell, 27, has missed both of Saints' Premiership matches at the start of the new campaign having suffered the injury during pre-season.

"He's had some treatment and we're waiting to see how effective that's been," Dowson told BBC Radio Northampton.

"We want to make sure that's as conservative as possible when it comes to things around the neck.

"So we're giving him some time to make sure he's 100%."

England face New Zealand, Australia, world champions South Africa and Japan across consecutive weekends at Twickenham next month.