Posh manager Darren Ferguson has emphasised that Day will be given an opportunity to stake his claim for the left-back position once he has recovered from an ankle injury.
"Jamie is very much part of our plans," Fergie told the Evening Telegraph.
"I have always liked him as a player and I certainly think he will cope in the Championship.
"It is not unusual to pick up a little injury and being out for so long but Jamie is ready for games in the reserves and he will be back in the squad in a couple of weeks' time."