Rajon Rondo’s anterior cruciate ligament rehab has been well chronicled, and Celtics followers breathed easier when he fossilized Pau Gasol with a fake on the way to a layup in last Friday night’s re-entry to the game. But it may well be an even more encouraging sign for the Celtics and their future that Rondo is working on more than just his right knee. He has been on a quest for intracranial improvement, as well, reaching out to a number of sources as he seeks to become a better leader, as recently when he wondered how much to get involved when two teammates had a disagreement. Though he has nearly always been a vocal presence on the club, he is essentially on his own now as the frontman in the Shamrock band. After yesterday’s practice Rondo acknowledged there are changes that come with the role. “It’s a lot different,” he said. “I’m going on 28, it’s my eighth year in the league and being the point guard, it’s just all about timing. It’s a great opportunity. “We’ve got a young team. I’m pretty much one of the older guys besides this guy right here,” he said, pointing to Gerald Wallace in the next chair on the sideline in the Heat practice facility. It should come as little surprise that Rondo has taken the studious approach to what has at times been a communication issue for him. It is an obstacle he intends to conquer, or at least meet halfway. “And it’s not just being a leader here,” he said. “If I want to go into coaching afterwards, it’s the next step to that, being a leader on the court and knowing how to talk to guys. You know, you can’t coach every guy the same way. Guys don’t take criticism the same. It’s a learning process, and I’ve been learning every year I’ve been in the league.” A born competitor, Rondo is rarely one to admit shortcomings. He opened the door a bit when asked if there are specific aspects he needs to improve. “Yeah,” he said, “the way I talk to guys. I’ve got to find better ways to get my point across. That’s in life though. It’s not just basketball; that’s in my relationships off the court. I’ve got to work on my delivery. My message is always good. It’s just the way I say it may be a little bit harsh.