Wayne Rooney has been confirmed fit for the derby this weekend.
The player gave his team a scare as he limped off after training at Carrington on Monday.
It is understood that the United Captain trained fully on Wednesday and will play at the Etihad Stadium on Sunday.
Rooney has been serving a three game suspension for a sending-off against West Ham.
According to the daily mail, United manager Louis van Gaal has told Rooney he will definitely start and it remains to been seen who will make way.
Robin Van Persie could be the one to step down after a series of indifferent performances but the more likely candidate would be Mata who was virtually none-existent in their game against Chelsea.