If a team is under the cap, that means the salaries don't have to match, for the trade to go through. However, you can't make an offer that puts the team that's under the cap over the cap. Ex: Let's say the Knicks are 10 million dollars under the cap. That means that they can trade for someone that makes up to 10 million dollars more than the player they are offering. By the way, I have no problems trading Zach Randolph. Nobody on the Knicks is untouchable, including him. I just feel the Knicks should try to trade Curry, because he's the least productive of the two. But if the Knicks trade Randolph, I wouldn't mind, as long as the Knicks get some picks and expiring contracts in return.