United were hoping that the 29-year old could join the squad for the summer tour, that now won’t happen and instead he will be receiving more treatment on his persistent knee problems.
Hargreaves only managed to make one substitute appearance for the first team last season, after coming through 45 minutes for the reserves.
Sir Alex told MUTV: "The bad news is that Owen Hargreaves is back in America seeing a specialist.
"He will not be ready for the start of the season. I do not know when he will be back."
I'm gutted for Hargreaves, he is a descent player who United have missed at some points during last season but is it now time to say enough is enough. Bring in a new player, who can do the same job as Hargreaves but is not constantly out injured.
