Powell may have to bide his time for a competitive debut but he too will be on the pre-season tour.
"I think in Nick's case, he's got a bit of physical development to do, just as we would expect of an 18-year-old. But he'll be in the first-team squad and train with us every day."
The England youth international could still make an early impact, however, in keeping with the proud traditions of Manchester United.
"Football throws up opportunities for young players and we play young players all the time," Sir Alex said.
Look out for more stories - and quotes from the new signings - on ManUtd.com this afternoon (Thursday).