Cruzeiro midfielder Everton Ribeiro has told ESPN Brasil that he would fit into the Manchester United side.
Portsmouth have named Richie Barker as their new manager and Steve Coppell as director of football.
The 30-year-old has struggled to cement a starting place since the arrival at Ewood Park of Henning Berg.
After 11 appearances in the Championship this season, Orr was an unused substitute in the 1-1 draw at home to Birmingham, having to make way for 18-year-old Adam Henley.
Orr's deal with Mick McCarthy's side is due to end on January 26.
The veteran defender moved to Ewood Park in January this year after a spell of nearly three years with QPR.