Patrick Ewing cringes at the perception he’s “just” a big-man coach. No one enjoys being pigeon-holed but Ewing is an accomplished big-man coach. He tutored Yao Ming in Houston and Dwight Howard in Orlando. And he played 17 NBA seasons averaging 21 points 9.8 rebounds and 2.5 blocks. Ewing hasn’t played since 2002 but players remember. That’s one of the reasons center Al Jefferson the most prominent free agent in Charlotte Bobcats history chose to sign here. “I knew about what Patrick Ewing did for Dwight Howard – a major impact. I knew that working with him was my chance to bring my defensive game to another level’’ said Jefferson whose defense has been frequently criticized over a nine-season career. “Pat said that for me to get the respect I deserve I have to pick my defense up. And I have the tools to do it. He can have that impact on me.” Ewing has gravitas. He was named one of the 50 greatest players in NBA history. That gives him a head start toward credibility which coach Steve Clifford believes is a prerequisite to accomplishing anything in the NBA. “Coaching in this league is all about credibility. There are different ways to establish that but these guys are fans and (Ewing and fellow assistant Mark Price) were terrific players’’ Clifford said. “That’s the start. The thing with those two guys though is their true credibility is once you get to know them: It’s clear they can help’’ players improve.