Jose Mourinho gives downbeat assessment on key Manchester United trio of Chris Smalling, Phil Jones and Juan Mata

London: Manchester United manager Jose Mourinho will hope no mishap befalls central defenders Eric Bailly and Marcos Rojo after announcing on Friday both Chris Smalling and Phil Jones will be out till "mid-May".

Mourinho, speaking after United returned from Belgium where they drew 1-1 with Anderlecht in the first leg of their Europa League quarter-final, added pivotal midfielder Juan Mata would be out till "late May", which could mean he misses all of the Premier League run-in.

The Spanish international, who has undergone a groin operation, is also at risk of missing the Europa League final on May 24, should United reach it -- Mata will be missed as he has been United`s most effective goalscorer this season apart from leading marksman Zlatan Ibrahimovic.

"There is nothing I can do (about the current defensive situation)," Mourinho told the club website.

"They (Bailly and Rojo) have to go until the limits. There is no other choice. We don`t have any other central defenders. They have to go. There is no other chance."

United, who play Premier League leaders Chelsea on Sunday, have a hectic schedule and face a fight to qualify for next season`s Champions League.

United are presently fifth in the table, four points off Manchester City and with a game in hand, but could also secure a Champions League slot if they win the Europa League.