"I had an unwritten agreement with Chris that if someone came in with a longer deal he could go, and we've stuck to that," Coppell told the official website.
"Scott has gone to get games under his belt. We've only got a couple of reserve matches and this will be competitive for him.
"Even the Premiership reserve league is not as good as playing sharp League Two football.
"You can't have a callback in the first month but I think it can be extended."