The quartet will be tied to Manchester United until at least the end of the 2018-19 season.
Manchester United have triggered 12-month contract extensions for four of their stars, which include Juan Mata, Ashley Young, Daley Blind and Ander Herrera - ensuring the quartet are tied to the club until the end of next season.
The four first team members would have entered the summer as free agents, but the Red Devils have looked to tie the players up and bolster their transfer value, ensuring the club avoid any complications while manager Jose Mourinho weighs up their long-term future at Old Trafford.
The clauses in each contract extends deals until 2019, with Mata, Young, Blind and Herrera joining Luke Shaw as members of the United squad who have received letters confirming their time at the club has been extended by another season - as per The Telegraph.
Blind has taken a back seat this season and the club is understood to be willing to listen to offers, while Mata's time at the club is said to be dependent on the future of fellow playmaker Henrikh Mkhitaryan.
Shaw is likely to be given the remainder of the season to stake his claim for a role at the club next season, with Young's age (33) the only factor which is currently a cause for alarm after impressing at fullback this term.
Marouane Fellaini is set to see his deal at Old Trafford end at the conclusion of the season, with the midfielder allowed to talk to clubs outside the Premier League this month. Besitkas are reportedly leading the race to sign Fellaini who recently turned down United's new contract offer.
Despite Fellaini set to end his five-year association at Old Trafford, Mourinho is not prepared to sanction a deal which would allow the Belgium international to leave the club in January for a small fee as he is willing to risk losing the midfielder for nothing in the summer.
Although having been plagued with injuries in recent months, the 30-year-old remains an important player for Mourinho.