The Redskins aren't going to draft FS Eric Berry with the fourth pick. Their sudden late interest in Berry almost certainly is to shop the pick. And you can be sure they've called the Eagles, who in this uninspiring yet deep draft might have Berry at the top of their board.
On the draft value trade chart, the Eagles would be in striking distance of Berry if they supplied teams drafting 4-through-7 - the Redskins, Chiefs and Seahawks - with their first-round choice and their best second and third-rounders. That would leave the Birds with one more second and third round choices.