Di Matteo believes Shorey, voted the best left-back in Reading's history in a fans' poll, will add valuable top flight experience to his squad.
"Nicky has completed a medical and we are hopeful he will become one of our players over the next 24-48 hours," he told WBA's website.
"We're quite far down the line with Nicky. We hope he will join us. Nicky will increase competition for places.
"He's composed on the ball and a good defender.
"It will also be nice to add some Premier League experience to the squad, because we are a young team. Nicky knows what it takes to play at the highest level."