The Red Devils playmaker is sidelined after undergoing groin surgery earlier this month.
As a result, the 28-year-old is unavailable for Sunday’s Premier League showdown at Old Trafford (4pm).
Jose Mourinho’s men have struggled to turn draws into wins when playing in Manchester this season.
But with Champions League qualification on the agenda, a positive result is needed against table-toppers Chelsea.
Juan Mata is seemingly gutted he won't be able to face Chelsea for Manchester United
We need mainly to get better at Old Trafford, at home
And Mata admits he would love to be involved, as do all of his United colleagues.
“We will fight until the end to be in the top four, and in order to do so we need mainly to get better at Old Trafford, at home,” Mata wrote in his blog.
“We have an opportunity the next weekend against the leaders Chelsea. It’s one of those games that everybody wants to play.
“I hope that things keep going well and I can be back soon to enjoy what I like so much: training and playing football.
Man United's £200m summer wish list Mon, April 10, 2017
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Antoine Griezmann (Atletico Madrid) – £86m
“[At Sunderland], Marcus [Rashford] closed the score with the third goal to keep the team in the battle for the Champions League spots.”
Manchester United travel to Anderlecht for their Europa League quarter-final first leg on Thursday (8.05pm), and the tie is just as important as the clash with Chelsea.
Mourinho knows qualification for the Champions League is more realistic via the Europa League.
But after Arsenal’s 3-0 defeat at Crystal Palace last night, fifth-placed United can still chase down a top-four finish.