Chillingworth was injured in a pre-season friendly against Leicester

The 26-year-old, who is in his second spell with the U's, recently returned to training after having an ankle operation earlier this season.

He will join City until 12 January to build up his match fitness.

Meanwhile, in his absence, United thrashed King's Lynn 5-0 on Saturday in the FA Trophy first round, with Scott Rendell scoring twice.