Mourinho has added Eric Bailly, Henrikh Mkhitaryan, Zlatan Ibrahimovic and world record signing Paul Pogba to his bloated squad.
But Saints chief Puel believes Mourinho will struggle to give his big names all the game time they want.
Puel, who takes his side to United tonight, said: “I don’t know how the manager can have all these great players together.
“It is difficult to remain a collective with two or three players for every position on the pitch.
**MANCHESTER UNITED TRANSFER NEWS: WHO DOES MOURINHO WANT? WHO HAS SIGNED? WHO COULD LEAVE?**