MLB.com's Todd Zolecki is reporting that, while everyone assumes trading Werth is key to acquiring Roy, it may not be the case:
The Houston Astros have scouted J.A. Happ's latest starts, which indicates he would be packaged in a deal for Oswalt. There have been numerous reports the Phillies would have to trade Jayson Werth to clear salary and gain prospects for Oswalt. But I have heard recently that is not the case. While the Phillies are exploring trade partners for Werth, they could acquire Oswalt and keep Werth. And if I'm the Phillies, that's exactly what I do, unless I get an incredible offer for Werth...
...But here is why I think getting Oswalt makes sense, regardless of how the offense is doing: the offense is what it is. The Phillies could add an infielder to help while Chase Utley is out, they could trade Werth and promote Brown to see if he could provide a spark, but I'm not convinced one player makes things better.