The 27-year-old has returned to the Millers after a successful loan spell with the League Two U's, where he scored one goal in nine appearances.
Oxford boss Michael Appleton is desperate to get the midfielder back at the Kassam Stadium but admits it is dependant on Maguire's situation in South Yorkshire.
"We certainly would like to do something and I know Chris, having spoken to him on Saturday, would love to stay," Appleton said.
"It's now down to him, his representatives and Rotherham. The frustrating thing from Chris's point of view is that he's in a bit of limbo.
"I know he would prefer to get some sort of settlement. Whether Rotherham are prepared to do that, we'll have to wait and see.
"The last half a dozen games, his fitness levels are where they should be. From our point of view, we're delighted with his contribution and hopefully he can contribute a little bit more."
Maguire asking to tear his contract up is unlikely to be a problem for boss Neil Redfearn, who does not see the former Sheffield Wednesday man in his plans at New York Stadium, though it is likely to come down to a financial agreement being reached.
Maguire has made just six starts in 15 appearance for the Millers since his summer switch from Hillsborough.