August 31 isn't the last day that trades can be made. It's simply the last day that a player can be traded and can still be included on a team's playoff roster. That doesn't mean we should assume that the Red Sox have any impending trades in the works, though, even if the Boston Globe's Nick Cafardo is reporting that a trio of relievers have been placed on waivers.
Daniel Bard, Mark Melancon, and Clayton Mortensen have all been put on waivers, according to Cafardo. Bard struggled as a starter, and then put up ugly numbers in Pawtucket trying to rediscover himself in the minors. The Red Sox might want to see just what kind of interest other teams have in him, given he's under contract for the next few years, but it's likely that it's not much besides Boston wanting to see what other teams think of him before the off-season begins. You know, just in case.
Melancon and Mortensen are probably on waivers for the same reason, or because Boston seems like they put everyone on waivers eventually, either to gauge value or to mask whatever their intentions are. Sneaky!