"Schuy might not make it this weekend and Simon is the next one in there," Gradi told the club's official website.
"He knows that and I will continue to work with him because he is a talented and skilful footballer, who wants to get his career going again.
"Simon's attitude in training has been first class and he wants to learn and do well. He came on at Cheltenham and he was trying to do what we had asked of him.
"He has to be more disciplined in that central midfield role and he is taking that on board."