After his impressive form for the Ukrainian side, Fred earned a move to England when United boss Jose Mourinho identified him as the man needed to help them push on and become a greater force both domestically and on the European stage.
United paid Shakhtar £47m for the Brazilian but he hasn’t been able to cement his place in Mourinho’s starting line-up.
When picked, Fred has failed to showcase the abilities that convinced Mourinho to bring him to Old Trafford in the first place.
However, Fonseca believes that in time, Fred will develop into the player United want him to be and once the Brazilian has fully adapted to life in England, he will become one of the greats.
“He’s a big talent and he’s still developing,” the Portuguese boss told ESPN FC.
“I have no doubt he’ll have a great future at Manchester United. But, of course, he needs time. It’s totally different from what he was used to in Ukraine.
“He needs a period to adapt, to the club, to the league. It’s a totally different situation.”
Manchester United’s next fixtures
Fred and his Manchester United teammates face Italian giants Juventus this evening in the Uefa Champions League before facing an equally tough trip to current reigning Premier League champions Manchester City.