Rodgers has now transformed Leicester City into title contenders after moving south from Glasgow in February.
Having worked with Rodgers personally, Mancienne told Tribalfootball it was obvious the 46-year-old would succeed at the top, especially with the help of perennial winner Mourinho.
"Most definitely [you could see Rodgers' potential]," New England Revolution defender Mancienne said.
"To be honest at the time he was learning from one of the best managers in the world in Jose Mourinho. I think he picked up a lot of things from him.
"But Brendan as a coach was great. His training sessions were really good, really enjoyable.
"You could always tell he had the potential to go on and do big things and he has."
Rodgers' work at Leicester City hasn't gone unnoticed by his Premier League rivals.
Speaking after Sunday's win over Everton, Rodgers acknowledged there could be such a clause, but insisted he was content at the King Power.
"Listen, there are probably clauses in most managers' contracts," he said.
"It's all hypothetical. We got a brilliant win. We came back very well.
"I made a change eight, nine months ago. I feel so happy. We still have a lot of work to do.
"I've been very fortunate to work with some brilliant clubs and great institutions. The ambition was to help the club to arrive in the top six."