Ander Herrera may be Manchester United's reigning player of the year but Jose Mourinho had no room for the midfielder in his squad for their Champions League opener. Marouane Fellaini, Romelu Lukaku and Marcus Rashford netted as United ran out comfortable 3-0 victors in Tuesday's Group A opener at home to Basle.Paul Pogba's hamstring injury was the only negative on a straightforward evening for Mourinho, whose strength in depth was laid bare by the fact Herrera did not even make the bench.Voted last season's Sir Matt Busby Player of the Year, the United boss confirmed his absence from the squad was down to the options at his disposal rather than injury."No reasons to be out," Mourinho said of Herrera, who has made just two starts this season."We are playing only with two midfield players, with (Nemanja) Matic and Pogba, which are playing really well and without reason to change."The only match that we decide to play with three (against Stoke) he played."Today we went back to two again and I had on the bench (Michael) Carrick and Fellaini, which were also important players in the last season."We have a group of players and the players must be ready to play and not to play."Ashley Young was not on the bench in the last match and today he started the match and he played for 90 minutes, and the next match you can have another surprise of some player that you think is going to play and is not going to play."It's the squad we have, I have to use the players and that's the life in clubs with squads of quality."Such is Mourinho's strength in depth that Carrick, appointed captain in the summer, has yet to get a minute of action so far this term.Marcos Rojo, Luke Shaw and Zlatan Ibrahimovic are others yet to feature as they return from injury, while Tuesday's match gave Chris Smalling and Victor Lindelof a first chance to play since the UEFA Super Cup.Eric Bailly and Phil Jones have started all four Premier League matches, but their European suspension led to a change at the back."(Smalling and Lindelof) train really hard," Mourinho said."They train together always in the same team because I knew that they had to play this match together."If you want to anticipate the next weekend (against Everton), I probably play Bailly and Jones because today they didn't play, because they are fresh, because it makes sense for them to play again."But then two days after we have a League Cup match (against Burton) so Victor and Smalling again."So we need this and in the Premier League and the Champions League I have to choose the players in relation to the quality."When I know that in the Premier League I'm going to face one of these defensive walls, probably Victor is the best to come with the ball, to attack spaces in midfield, to find people in-between the lines."So what I want is to have the players available and sometimes they are not playing, but for me as a manager it's important to have options."