Some general managers warn to change the trade deadline from July 31 to Aug. 15 next season. Though Cubs G.M. Ed Lynch's proposal to move the deadline at last year's general managers' meeting was rejected, there's increasing sentiment that teams are too uncertain about their wildcard prospects with more than a third of the season remaining to cut off trading as early as July 31. The dilemma is exacerbated by the unwillingness of today's G.M.'s to honor the old gentlemen's agreement that used to make it relatively easy to make swaps after the deadline. Until recently, most teams didn't put in waiver claims simply to block deals, but last year, according to Lynch, there were more than 130 claims, making it almost impossible to deal players once the deadline had passed.