19-year-old McGuane surprised many when he joined the Catalan giants from Arsenal for undisclosed fee in January.
He has since played for Barcelona B, who currently compete in the second tier of Spanish football.
But McGuane has been included in Ernesto Valverde's squad, along with 11 of his teammates, for the Catalan Super Cup final against Espanyol on Wednesday night.
Barca B coach Gerard Lopez told ESPN FC: "In a short time he has already earned my confidence, and I hope he can become an important player for us.
"I can use him in a lot of positions and at his age, he still has a lot of room for improvement."