Assuming that Chad Santos isn't the answer, here's an attempt to break down the Sean Casey rumors. You will also note the games from the weekend will not be discussed:
Houston (though the hole is filled when Ensberg comes back from the D.L.)
That's it. The Pirates have two first basemen to deal, though Craig Wilson can field poorly at other positions too. Other teams will want Wilson off the bench or in the outfield, so there might be a bit more competition for his services. But it is most assuredly a buyer's market for first basemen. Looking at the list of suitors, I just don't see how Sean Casey isn't a Giant by August.
Sabean: No, you don't.
Pirates G.M.: Yeah, he's a part of the rebuiliding plans.
Sabean: No, he isn't.
Pirates G.M.: Yep. I'll need Sanchez, Hennessey, and this Frandsen kid to start.
Pirates G.M.: Yello? Yelllllo?
The Angels have two underperforming prospects in Kendry Morales and Casey Kotchman, and might be in the market for a rent-a-player. Kotchman has mono, which I struggled with personally for a heck of a long time, so there are no guarantees he'll be back. Oakland would be better served to find an outfielder to replace Jay Payton, rather than give anything of substance for the modest upgrade of Sean Casey. Houston just traded for Aubrey Huff, who will go to the outfield when Ensberg gets back.
The Giants and the Angels are the only two suitors, with the Angels optimistic that a young player still might step up.
Sabean: So are you ready to stop jerking my chain?
Pirates G.M.: Hey, you're the one calling me an hour before the deadline. I hold the chips here. Hold on, I have another call.
covers the phone with his palm, and imitates the ringing of a phone
Pirates G.M.: Brrrrring! Brrrrrrrring! Hello? Well, well, well. Mr. Epstein, how nice to hear from you! Actually, Casey is still on the market. Funny you'd ask, as I was just about to deal him to San Francisco.
Sabean: If you really took another call on the same phone, I wouldn't be able to hear this.
Pirates G.M.: I'll tell you what, Theo, I'm going to have to get back to you. Sabean knows you're not really on the phone. Mm hmm. Mm hmm. Right. Well, thanks for calling.
There is a twist, as Casey is from the Pittsburgh area and might want to stay with the Pirates. A new contract could be worked out between the two, should Casey stay. The Pirates might have some weird reason for keeping Casey as some sort of hometown draw. It worked out so well for the Giants and Tyler Walker.
In a sane world, however, the Pirates have absolutely no reason to hold on to Casey. He wouldn't be a part of the next contending team in Pittsburgh, he isn't exactly Mickey Mantle in terms of drawing power, and the Pirates still owe millions to Casey. Millions. As in, wouldn't they be better served tossing those millions to the next amateur player who slides down to the sixteenth round because of a strong commitment to a university? Or starting the first international scouting program in Paraguay? Or anything that doesn't involve holding on to a marketable commodity at the expense of a rebuilding team?
Sabean: Merkin Valdez or Alfredo Simon. Pick one and I'll fax over the paperwork.
Pirates G.M.: Are you crazy?
covers the phone with his palm again
Pirates G.M.: Brrring! Brrrrring! Hello? Is this, uh, Mr., uh, Angels G.M.? Yes, Sean Casey is still available. Right. Right. What do you mean you aren't going to offer anything more than a career minor leaguer? You aren't even on the phone. I'm making this whole conver.... Right. Okay. I can see that. Well, if you change your mind, you know where... Hello? Yelllo?
If there is really a strong mutual interest between Casey and Pittsburgh, he could always pull the Sidney Ponson move; force a team to give up prospects for him, and then resign with the old team. It worked out so well for Baltimore. It's kind of a Jimmy Hart/Andy Kaufman move, but it isn't against the rules.
The Vogelsong karma was paid off tenfold with the Minnesota trade, so any sympathies along those lines are misplaced. The Giants are willing to pay the rest of the salary. They'd be fine with including Lance Niekro, I'd imagine, in addition to whatever else the Pirates would want. Casey isn't Carlos Beltran from 2004, so the Pirates shouldn't hold out for any of the top young pitchers in the Giants' organization. They have every reason to trade Casey at a discount, and the Giants have every reason to want a discounted Casey. The Angels might give chase, but they would be the only competition if they do.