I don't think they need to add anybody at this point. What they need is to get their own house in order.
They need to straighten out their starting pitching. Get Morales back as a starter--in place of Cook.
Put Ciriaco at SS instead of Aviles--who has been stuck in cement far too long there while Iglesias is rotting in Pawtucket. If Ciriaco can't hack it there defensively, bring up Iggy.
Bring up Lav and have him competing with Salty. Carry 3 catchers and one less pitcher.
Lav is a Yale grad, and should quickly pick up calling games properly.
I would deal some of their excess--Shoppach, Sweeney, Albers. They will need spots for Bard and Bailey soon.
If they dump Beckett, they have somebody for that slot--Cook, Morales or Aviles when Bard/Bailey return.
I think Crawford should get his operation now unless they can deal him. He's almost useless the way he is being used. They won't let him steal a base--which is half his game. It's pretty laughable. What a f**king horrible organization. Who knew it would come to this. But collapses don't happen without incompetence in the management.