Former Manchester United coach Mike Phelan believes Louis van Gaal is partly responsible for Manchester United's current injury crisis, reports the Manchester Evening News.

Chris Smalling became the 42nd player to suffer injury for United this season when substituted in Monday's game at Southampton, and van Gaal has already used 37 players in just 16 matches this term.

And Phelan - who assisted Sir Alex Ferguson between 2008 and 2013 - says the removal of fitness coach Tony Strudwick has played a key part in the injury crisis at the club.

"What's happened is a continuation of the same players getting injured all the time, so you have to look to the reasons why," Phelan told the International Business Times.

"I think Manchester United changed their thoughts on the fitness regime, they looked at it a little bit differently.

"Tony Strudwick, who was operating as head of sports science, was involved day to day with the first team.

"He understood the ins and outs of how to keep players fit, how to keep them ready for competition.

"Then suddenly they moved him sideways and did something completely different. That may have had an effect. That one area has changed."

"They've brought in new people with a different way of doing things," Phelan added. "The intensity of training may be one thing - it may be too intense, or not intense enough - but obviously slight changes have been made with the present way of doing things.

"I would have thought [the squad] is big enough at Manchester United, because they can go out and get players in, but obviously they keep breaking down and they don't seem to be getting any better.

"They seem to get one back and lose another two.

"Van Gaal knows now roughly the intensity of the Premier League and what his players can produce. He's been at the highest level, working with the highest players, in different countries.

"It's just a case of maybe understanding the specific requirements of players, individual players, where they need to be at certain times in order to perform. He's got enough staff there to sort that out."