The Chilean made an immediate impression after coming on as a half-time substitute against Bournemouth.
"You've got to remember Angelo's only 18 - it's tough and he's not yet played a league game over here yet," Pollitt told the Wigan Observer.
"He played a few senior games in Chile and it's a different kettle of fish. He's had a little spell at Manchester United for six months, found his feet a little bit. He's only really played the Under-21 league, so it's a bit step up for him playing against senior players in the FA Cup.
"But this will give him a bit of confidence. He's getting to know the lads a little bit more and we're going to be looking to play him more now with Arouna going away.
"It's a chance for him to come and try and impress.
"At the end of the day, he's a Manchester United player, so it will be good for them as well if he gets some games under his belt and come experience here."