The Knicks are making progress on a deal that would bring Sixers forward Keith Van Horn to Madison Square Garden, according to a league source.

Latrell Sprewell is the player the Knicks would prefer to deal but Philadelphia does not want to burden its first-year coach, Randy Ayers, with the responsibility of trying to make a lineup of Sprewell and Allen Iverson work. Instead, the Sixers would be willing to trade Van Horn for Kurt Thomas. Other players, most notably Charlie Ward, would have to be included in the deal for salary cap purposes.

But for the Knicks to move Thomas, their starting center, team president Scott Layden would have to find a suitable replacement either through a trade or a free agent signing. Until that time, Layden will not pull the trigger on a deal for Van Horn.

Layden and Sixers GM Billy King spoke face-to-face yesterday for the third straight day at the Reebok Pro Summer League in Boston. The two executives have discussed a deal for Van Horn since January. It is conceivable that if a trade is consummated it would not take place until sometime in August, once the Knicks either obtain a center or are confident they are on the verge of making a deal for one.

Coincidentally, the Sixers have two free agent power forwards - Derrick Coleman and Tyrone Hill - who, like Thomas, can play center.