Jose Baxter is currently out for a year due to a suspension because of drug abuse. Traces of cocaine were found in his blood and the suspension is to end in February.
"I'm speechless. Not many people get a second chance and here's me with a third chance," he told The Times.
Unsworth added: "It can be anything he wants it to be. As soon as he comes through the gates of Finch Farm in July, he will be treated like an U23 player and we work very hard.
"He will be given the same opportunities as everyone else. If that means he moves on to a Championship club or League One club later on, that will be down to Jose.
"We want to help because that is the sort of club we are. He is one of our own, but I have said to Jose, in no uncertain terms, that this is your last chance."