Clarke is impressed by Di Matteo's revival after his sacking by WBA.
The Albion boss said: "If someone has taken you up to the Premier League, you'd expect them to stick around a bit longer.
"It was probably painful at the time but Robbie bounced back really well from it. I didn't see him as a future manager when we played together. Some people maybe, but it was a 'No' to Roberto. But he was devastated when he had a bad injury that forced him to retire.
"Then when I was coaching the youth team one day, he was standing by my side and asking me questions. I'm not surprised he's done well as he's a very deep thinker.
"I've been impressed with the way he's handled everything at Chelsea. He's a good man and a decent person.
"I hope Robbie will get a warm welcome - he'll certainly get one from myself and the staff."