"The mighty Liverpool in years gone by once won the league with only 15 players," said the Royals boss.
"Times are different, I know that, but you can't question it if he is winning games and trophies. That is the bottom line.
"If the rotation is between fabulous full internationals and kids straight from the reserve team there is obviously a problem. But when you are replacing one top quality international with another it is not that big an issue.
"I have no idea what their team will be. I know Sir Alex Ferguson said the other week it is difficult preparing for them as you don't know what they are going to throw at you but as far as we are concerned they are going to be good players.
"We know their style will be a passing game with terrific individuals so I fully expect to be playing 11 internationals."