his Barclays Under-21 debut against Blackburn Rovers recently.
"I've not had two or three players as they have been up with the Under-21s most of the time," explained McGuinness to ManUtd.com. "We've not had James all of the time but he's played some games. Andreas has only played a couple and Saidy has only just come in. I'm looking at how they fit in and, when it comes down to it, you have to pick the best team to win the game in the Youth Cup, like you would with a professional team.
"It doesn't necessarily mean the best players all the time. You might have two good players for one position or just think somebody has got more determination and passion to play and deserves it more than somebody else.
"Quite a few of them are making good progress and need to keep that going in both the league and the cup. We've used the squad and other people have had an opportunity in the Under-18s and that is good because it keeps everybody in the hunt and wanting to do well."