The Bulgarian striker hurt his ankle in training so is unavailable for the second fixture of the US tour while the late arrivals to the squad will not be involved - even though there has been plenty of speculation that David de Gea could make his debut, sharing goalkeeping duties with Ben Amos.
"Berba had a knock on the training ground towards the end of the session," explained Sir Alex to MUTV. "So he is out. No [the latecomers] won't be involved. They'll play in Chicago. De Gea won't play but he'll play in Chicago."
Tom Cleverley, Danny Welbeck, Chris Smalling and Phil Jones won't be considered for selection but the boss is pleased with how the players have stepped things up following the win against New England Revolution.
"I think we're more ready now," he added. "Preparation has been good this week and training has been terrific. I think we'll be much sharper. Training has improved in terms of quality and speed so I'm looking forward to it."
The full interview with Sir Alex will be on MUTV ahead of exclusively live coverage of the Seattle match, with Countdown to Kick-off starting at 10pm BST.