The quartet were all set to become free agents in the summer.
Manchester United have extended the contracts of Juan Mata, Ander Herrera, Ashley Young and Daley Blind.
All four players were set to become free agents when their deals expired in the summer but United have decisively secured their immediate futures with the club, as per The Telegraph.
By triggering 12-month clauses until June 2019, it increases the transfer value of each player and puts United in a slightly stronger position, in terms of negotiations with other clubs, should they receive bids.
Marouane Fellaini is another player out of contract in the summer but it appears as though United boss Jose Mourinho is prepared to lose the Belgian midfielder for nothing in the summer. Mourinho does not want to sell Fellaini this month as he considers him to be an important member of the first-team.
Blind and Herrera have not been guaranteed starters at Old Trafford this season. The versatile Dutchman has found it difficult nailing down a place in the starting line-up while the arrival of Nemanja Matic from Chelsea last summer pushed Herrera down the pecking order.
Mata’s future is unclear in the long-term but the Spaniard has continued to put in strong performances in the first-team recently, including scoring a brace against Leicester City.
Young is a different story. The veteran full-back has been one of the more consistent United players this season but will be 33 next year. With Blind and Matteo Darmian’s futures uncertain, the signing of a top-quality full-back will almost certainly become a chief priority for Mourinho next summer.
Having secured extensions for those four players, it means Fellaini, Michael Carrick and Zlatan Ibrahimovic are all set to leave the club in the summer. Carrick is expected to retire, having barely featured this season after undergoing a heart procedure, while the popular Swedish striker is 36 and is not expected to stay beyond next summer.