Manchester United midfielder Michael Carrick has conceded that former assistant manager Carlos Queiroz will be difficult to replace.
Queiroz stepped down from his position at Old Trafford last week to succeed Luiz Felipe Scolari as head coach of Portugal.
United boss Sir Alex Ferguson has since insisted the club are in 'no hurry' to appoint a new No.2.
Carrick, though, admits it could prove difficult to find a replacement for Queiroz after the Portuguese played an instrumental role in the club's recent success.
"It's always sad to see people leave the club and Carlos was obviously a big part of things here," Carrick told MUTV.
"He had a big say in the running of the club with the boss, but he has left to do something different.
"As players we can appreciate that and we wish him all the best."
The England international also outlined the Red Devils' hopes for further glory in the new season after they secured the Premier League and UEFA Champions League double last term.
He added in the Daily Star: "We have to earn it all again after last year and we know it's going to be a long, hard season, but we're ready for the challenge."