Mourinho is widely expected to leave his position with Real Madrid at the end of the season, with a return to former club Chelsea seemingly on the cards.
"I know he was happy here because he had a good job at a good club and we were successful. That's what he likes, he likes to win football matches wherever he is," Clarke told Sky Sports News.
"If he comes back, it's great for the Premier League. If he does come back and we get the chance to play against him that would be great."
Clarke acted as assistant to Mourinho during the Portuguese's spell in charge at Stamford Bridge.