"Chauncey Billups, who missed last night's Game 2 thriller to the Celtics with a strained left knee and said before tip-off he would have an MRI exam today in New York.

Billups, 34, has not been ruled out of Game 3 Friday in New York, but it does not look very promising, as he was still hobbling in the locker room.

"I don't know. I'll find out more [today]," Billups told The Post after the game. "Of course I'm concerned. It's feeling better today as far as walking and stuff. Hopefully it will continue to get better."

And if he does return during the series, it would seem highly unlikely he will be close to 100 percent. Billups also has a $14 million option for next season that must be exercised by Knicks team president Donnie Walsh.

The Knicks, who lost 96-93 in Game 2 last night, trail 2-0 in the best-of-seven series, losing by a combined five points as Billups was joined on the sidelines by Amar'e Stoudemire because of back spasms.

"It is heartbreaking and looking at the potential of what could be," Billups said. "We should be up 2-0 in this series, even with us being banged up. It hurts."

According to a medical dictionary, a strain is considered an injury of muscles or tendons in response to a quick tear, twist or pull of a muscle. Pain weakness and muscle spasms are common symptoms. A sprain, however, is related to the ligament and considered more serious."