The defender was absent for both of United's Premier League outings so far, including the 4-0 win against Chelsea at Old Trafford and last Monday's 1-1 draw at Wolves.
Fans have been confused by the Portuguese defender's absence so far this season despite impressing last term, assuming he had been dropped.
The manager said: “It is more or less the same (squad).
“Diogo is injured, he'll be out for a little while, hopefully he'll be back for (the games) after the international break. He's had a problem for a couple of weeks. But that's it."