The Celtics traded Kendrick Perkins because they were convinced Shaquille O’Neal could be a more-than-adequate replacement at center and the team would flourish offensively.

Coach Doc Rivers acknowledged the Shaq experiment was a failure. The organization unwisely depended on a 39-year-old who had played nearly 50,000 minutes. The Celtics never had a healthy presence in the middle and their lack of interior defense was a primary reason why they were eliminated by the Heat, 97-87, last night in Game 5 of the Eastern Conference semifinals.

The Celtics were 33-10 before Perkins returned from a knee injury and the club was banking on that success in the second half of the season. O’Neal was unable to even step on the court for all but one regular-season game after Feb. 1. And in that April 3 appearance against Detroit, he strained his right calf.

“Yeah [it’s been a failure], it’s just nothing he can do and it’s not like he’s not trying,’’ Rivers said before the game. “I told our team that [Tuesday]. He’s done everything you possibly can do to get healthy and unfortunately for him, he just hasn’t been able to do it. When he was originally injured, no one even thought it was that serious. I think I said it’s not even a big deal, he would be back in four or five days. It just never healed. It still hasn’t and every time he plays it gets worse.’’