Jose Mourinho will stick with Sergio Romero as his Europa League keeper, insisting De Gea won't play the final.
"They are two fantastic goalkeepers".
Bailly's omission from the Europa League final adds to a growing list of unavailable players, with Mourinho already having to deal with seven injuries within his side.
Manchester United midfielder Ander Herrera believes they were forced to suffer in qualifying for this season's Europa League final.
So, winning the Europa League know becomes top priority for the Portuguese tactician, as the victor of the competition enters the Champions League.
"First of all, (they are) two monsters", Mourinho said.
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"We have Spain's national team goalkeeper [De Gea], Argentina's national team goalkeeper [Sergio Romero] and we have a young boy that, for me, is going to be the Portuguese No1".
United managed to keep Celta at bay during the six minutes of stoppage time until the very last kick of the game when they were given a huge let off due to Guidetti's poor control.
So impressive since arriving from Villarreal last summer, the 23-year-old Ivory Coast global was shown a straight red card for raising his hands during a heated end to the 1-1 draw with Celta.
"We need three good goalkeepers".
Mourinho revealed the Spanish global has accepted his decision, he said: "There's no dilemma, They are two fantastic goalkeepers".
"So if he doesn't play the final, he has to play the remaining matches in the Premier League and give rest to some of the others". This game will not mean a lot to Mourinho as he showed in his last few games so I am expecting a weaker side on the pitch so it seems unlikely the Red Devils will have what it takes in them to win this game.