Doc Rivers is off on a golf course somewhere, pondering his future with the Celtics and asking for time to think. But that hasn’t stopped the Celtics coach from taking regular part in the team’s plans for next year, according to president of basketball operations Danny Ainge. “I talk to Doc all of the time, and we’re talking about our plans for next year,” said Ainge, who left yesterday for Chicago to attend the NBA’s pre-draft combine. Though Ainge is unsure of whether Rivers will make an appearance in Chicago, he continues to move forward as the coach will remain in place. “I only expect Doc to say something to me if he is not coming back,” Ainge said. Ainge claims not to put much stock in anything a player or coach says in the wake of elimination. Rivers made mercurial comments about his future in Boston following the C’s elimination by the New York Knicks in the Eastern Conference quarterfinals. As Ainge knows from personal experience, what gets said on the podium in the minutes following a season-ending loss is generally not bankable. “Coaching is a grind, and playing is a grind,” Ainge said. “I never get caught up in what anybody says right after a season is over. I don’t ever think these discussions should happen at that stage. It’s always wise to let things settle and evaluate the whole season before you make a decision. I like to do the same thing as Doc is doing right now, and get away for a little bit to think about things.” Though Ainge regularly talks with Rivers, he said he has not had contact with either Paul Pierce or Kevin Garnett, whose futures figure prominently in his immediate plans. The Celtics have the option to buy out Pierce for $5 million by June 30, or retain him for $15 million for next season. Garnett, who has expressed a desire to play with Pierce, is under contract for two more years for $24 million, and he could easily be traded if the captain leaves.