Phelan confirmed there will be changes this evening - for example, both Darren Fletcher and Nick Powell will feature - but with the quality and size of United's squad he insists there are plenty of players capable of coming in and putting on a good display.
"We've got options and we have to make sure this game helps us involve other players as well as the ones who have been playing in the last five or six games," he told ManUtd.com. "It's important we give them the opportunity to perform.
"We've got a good mix of youth and experience and we want to make sure we perform and the players involved show their abilities and what they can offer.
"The manager has always seen these games as an opportunity to look at individuals' progress, to see where some players are at and if they're capable of being part of a long season. The hardest part is giving them the competitiveness and the games in order to prove that. You don't just want one game, either - you want more than one. And hopefully this cup competition offers us that."