The field of free-agent starting pitchers is mediocre at best, and the available catchers aren't even that good. The Mets, therefore, are prepared to trade to fill both needs even if it means draining their core of enticing players. "I think so, yes," General Manager Omar Minaya said yesterday when asked if he could trade for a catcher and a top-flight starting pitcher. "It all depends on how much the trade is going to cost. It doesn't have to be the farm system. It could be major-leaguers for major-leaguers." The most prominent major-leaguer to be traded could be reliever Aaron Heilman who still has value among opposing teams. The Mets have long held Heilman out of trade discussions, but Minaya clearly wants to pull off a big deal. "They're going to be active," one official from an American League club predicted of the Mets. "They're going to use those guys as trade chips and try to get some pitchers back."