Knicks president Isiah Thomas is sick of the skepticism surrounding Allan Houston and his conserva tive knee rehab.

“Allan Houston is not as big question mark in my mind as it is in your mind,” Thomas told re porters yesterday. “Any caution being taken with Allan, that’s coming from me. It’s really not coming from Allan.”

Houston, battling ar thritic knees, said earlier this week he’d take it easy during training camp that starts Tuesday in Charleston and said it’s “not a lock” he’ll play on opening night, Nov. 3.

“If we had a basketball game tonight, and we needed Allan to play, I am supremely confident he can go out and play well,” Thomas said. “We don’t want Allan to play one basketball game or play for three months. We’re looking at three more years.

“You haven’t seen him from last year, the way he was limping. I’m confident we’re going to have a good player.”