The contract extension offer Kendrick Perkins turned down was actually closer to four years, $22 million than four years, $30 million. (CSNNE)

And the preliminary offer made by the Celtics, according to Perkins, won’t cut it.

Perkins told CSNNE.com prior to Boston’s 94-89 loss to the Charlotte Bobcats that the offer made to him was for four years around $22 million.

An earlier report by the Boston Herald cited two unnamed sources that indicated Perkins turned down a contract extension that was for four years and worth slightly less than $30 million.

“That wasn’t it. They offered me four years, but it was closer to like $22 million,” Perkins said. “You talking four years, $30 million! Shoot, that’s different. That’s a big difference.”

It makes sense that the deal wasn’t closer to $30 million — because the Celtics CAN’T, by NBA rules, offer Perk that much money. According to Chris Mannix and confirmed by Larry Coon, resident salary cap doctor, the Celtics can offer Perk a four-year extension worth no more than $23.4 million. If Perkins opts to become a free agent, Boston can raise that offer. And Perk has already said he can’t see himself anywhere but Boston.

The limiting factor to Boston’s extension offer is a rule limiting the raises to contract extensions. According to Coon’s salary cap FAQ, “For all [non-rookie contract] extensions, raises are limited to 10.5% of the salary in the last year of the existing contract.” But the Celtics are unbound by that rule if Perk enters free agency, at which time they would be able to offer Perk a contract up to the maximum salary. Not that they would, of course. But, if they wish, they’ll be able to.

Obviously, this information all depends on the current CBA. Under the next CBA, these rules could all be different.