The Reds' boss revealed to Sunday's papers that eleven of his players, including Wayne Rooney, Ryan Giggs and David De Gea, have been named in preliminary squads for the Olympic Games which are being held in London in July and August.
A number of other players will, of course, be playing in the European Championships in Poland and Ukraine in June, while Sir Alex also confirmed that a handful of his budding youngsters have been chosen for a tournament involving England U19s.
"It's not an easy spell for us," admitted the manager. "There are so many complications attached to it [the summer]. You've got the European Championships, the Olympics and our pre-season tour.
"De Gea is definitely in the Olympics for Spain so we're missing a goalkeeper. [Javier] Hernandez has been called up to the Mexico squad. And then nine players have been nominated [for Great Britain].
"Ben Amos is one which would only leave us with one goalkeeper to start the season with. Giggs and Rooney have been nominated. Scholes hasn't. Ashley Young is in there too with Smalling, Jones, Welbeck and Cleverley. Jonny Evans is also nominated. If a player wants to play they play.
"The England U19s are also in a competition and have nominated five of our players who are meant to be going on our pre-season tour. It doesn't just affect pre-season, it affects the start of the season as well."
Anders Lindegaard, Patrice Evra and Nani are all expected to play for their countries at Euro 2012, while Jones, Ferdinand, Smalling, Welbeck, Cleverley, Rooney, Carrick and Young are all in