Asked earlier this week why his Manchester United side are languishing in eighth, Mourinho was scathing of his clubs lack of investment in the summer by replying: Every team got better and we didnt.
It was hardly the pick-me-up that £53million summer signing Fred needed after a disjointed, disappointing start to his Manchester United career.
The Brazilian was not even named in Uniteds 18-man squad for the visit of the Gunners and was an unused substitute four days earlier in a 2-2 draw against Southampton.
Fred started each of Uniteds first four league matches this season but has made just three league appearances since and his absence – especially given Uniteds form – has confused supporters.
Mourinho claimed on Friday that Uniteds lack of balance in midfield has been to Freds detriment, suggesting the Brazilian will not be integrated fully until the Red Devils sort their defensive problems.
Mourinho on Fred's start at Manchester United
Step by step. You also have other players in other clubs that needed their time, and you have some of them that played even less than Fred. When the team is defensively stronger and doesnt need people in midfield that are more worried about giving some balance to the team than being involved in creation and attacking dynamics, I think the horizons for Fred change completely.
While Uniteds defensive problems have undeniably limited Freds opportunities, Metro.co.uk understands the Mourinho and his backroom staff are concerned that Fred is not yet ready to deal with the physical demands of the Premier League.
United are convinced of Freds long-term future at the club and were buoyed that they beat rivals Manchester City to his signature but Mourinho believes the midfielder needs a longer adaptation period at Old Trafford to adjust to life in England.
Fred has been put on a tailored strength and conditioning programme to help him acclimatise and United feel hell improve as the season progresses.
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Mourinho is wary that integrating Fred into Uniteds midfield has been made difficult by the clubs inconsistent form and he feels the side lacks a strong enough base to allow the Brazilian to flourish.
Nemanja Matics form has been a source of concern throughout the season but Mourinho has stuck by the Serbian and instead taken his anger out on Paul Pogba.
The Frenchman was dropped to the bench for the visit of Arsenal but Mourinho extended an olive branch to Pogba in his post-match press conference by saying he was very happy with his performance when he came on.
Nevertheless, Mourinho has been scathing of his midfield options in recent weeks and claimed after the draw with Southampton that he lacks mad dogs to play with the intensity he craves.
The criticism doesnt necessarily apply to Fred but Mourinho has avoided leaning on the Brazilian throughout the clubs patchy start to the campaign as he feels a duty to protect him from what has been so far been a disastrous third season at Old Trafford for the Portuguese coach.
United host Fulham at Old Trafford today, looking to win their first Premier League match since their 2-1 win against Bournemouth on November 3rd.
Given his absence in recent weeks and Fulhams weaknesses in midfield, Fred could feature against Claudio Ranieris men but its clear hell have to be patient to make a breakthrough at the Theatre of Dreams.