League sources said the extension is for five years and guarantees Rondo at least $55 million. With the two sides facing a Monday deadline to get a deal done, Duffy said he called Celtics president Danny Ainge on Sunday to inform him Rondo was prepared to play out his contract and become a restricted free agent next summer because they weren’t satisfied with the team’s previous offers. Ainge, however, surprised Duffy by responding that Rondo’s contract hop...