Jose Mourinho is reportedly unhappy with Manchester United's medical department and is investigating all aspects of first-team affairs.
The Portuguese publicly questioned the mentality of defenders Luke Shaw and Chris Smalling earlier this week after the duo pulled out of the trip to face Swansea City.
Mourinho blamed the 'general culture' at Old Trafford for the withdrawals, which is thought to be in reference to players failing to give their full commitment to David Moyes and Louis van Gaal - and now himself - since Sir Alex Ferguson stepped aside in 2013.
According to BBC Sport, the 53-year-old believes that standards are slipping behind the scenes at Old Trafford and he is now looking at every area in his remit to put things right.
It is claimed that Mourinho will focus on aspects such as travel, pre-season tour planning, general fitness, sports science and the overall make-up of his squad.
United spent big in the summer but are currently sixth in the Premier League, sitting eight points adrift of leaders Liverpool after winning just two of their last eight top-flight outings.