By Wayne Veysey | UK Correspondent
Robin van Persie is at odds with David Moyes over the new Manchester United manager's training methods.
The Dutch striker has told close friends that he is "disgruntled" at the greater emphasis on running and endurance in sessions under Moyes' coaching staff compared to the Sir Alex Ferguson regime.
It is understood that Van Persie believes he is being overtrained, which is making him more susceptible to injury. The player has also expressed his frustration that Rene Meulensteen, the former United first-team coach and his fellow Dutchman, was not retained by Moyes this summer when he succeeded Ferguson.
Sources have said that Van Persie and Moyes exchanged heated words in the build-up to the Manchester derby after the 30-year-old suffered a groin injury in training, which kept him out of the 4-1 defeat at the Etihad Stadium.
It ended a remarkable run of 90 consecutive Premier League appearances at both Arsenal and United for the once injury-plagued Dutchman, which stretched back to March 2011.
Van Persie is believed to have blamed the training methods for the injury, while Moyes later hinted that the player and the staff did not see eye-to-eye over how serious it was.
"I don't think his injury is that bad," Moyes said in the aftermath of the Manchester derby. "We felt he was going to make it but he just felt something in his groin.
"He'd actually done some training in the last couple of days but he just felt it when he made any sharp movements and didn't want to aggravate it so we took that decision."
Van Persie subsequently missed United's Capital One Cup win over Liverpool and was only a substitute in the 2-1 league defeat to West Brom that followed.
The 30-year-old has started the last four matches for club and country but he came off at half-time during Netherlands' 2-0 win over Turkey in midweek.
The Dutchman is understood to hold strong views on match preparation and rehabilitation, believing heavy-duty sessions do not suit his explosive style of play, body shape and the advanced stage of his career.
In contrast, Van Persie's strike partner, Wayne Rooney, has spoken of how Moyes' methods have reaped their rewards in terms of his own personal fitness.
"It's a bit different in terms of David Moyes and his staff coming in," explained Rooney during the recent international break. "The training is different, there's a different style, a different way of thinking about how he wants us to play. Honestly, the training has been so hard. We've done a lot more running. Long running, quicker running, sharper running.
"I feel that's really benefited me. I feel as fit as I ever have done. I had a couple of injuries pre-season but I feel great and in good shape. It's a mixture of things, but I am happy and I am enjoying my football."