He said: "Richard has a real appetite for learning. He turned down the offer of a new contract at United to come here. That tells you everything you need to know about him.
"He wants to play week in, week out and we are delighted to have him on board.
"As for Brian, he's had a tremendous upbringing at Hamilton. It is up to him to evolve and show he is capable of playing at this level. If he does that we have a real asset on our hands.
"What both boys have in common is they are versatile defenders and that helps us."