They will be signing someone familiar with the playbook I'm sure. If it's a WR, it'll be AJ Jenkins most likely. Pure speculation on my part but I would assume it is someone they already have worked out or are familiar with...
As an aside, I want more Gavin Esocbar. Split him out wide like Gronk and Jimmy Graham. He could be a match-up nightmare. Hope Dallas borrows from the Pats and Sean Payton regarding creativity with their TE's. Those teams featured the TE without having all world WR's.