Mark Jackson came out of his shell in the playoffs, emerging as an important voice in the Knick locker room. But it was too little, too late. Now Jax promises to be a leader from Day 1 of training camp on a fractured club desperately needing one.

Jackson has been a regular at Purchase the past month. Yesterday, he ran 3 ½ miles across campus roads with trainer Mike Saunders in the baking August sun. “Absolutely,” Jackson said, when asked if he aimed to be more of a leader next season. “This is where it starts – coming down here, putting time in, being ready. It was a tough situation, coming here [Feb. 23], trying to do the things I’ve always done without stepping on toes. The great thing now is it’s a fresh start.”