The Mariners agreed to terms with Corey Hart this afternoon. Almost immediately thereafter, they traded Carter Capps to the Marlins for Logan Morrison. It's unclear to me what the Mariners will do with these guys -- Hart is probably a first baseman or a DH, and so is Morrison, but the Mariners also have vacancies in their outfield.
The Pirates had never seriously been connected to Hart, but the removal of Hart and Morrison really constricts the first-base market. James Loney remains, as does Kendrys Morales. Morales isn't very good and will require the loss of a draft pick, so it's hard to see the Pirates signing him. (I assumed he'd end up back with the Mariners, who wouldn't care about his defensive shortcomings; I'm not sure where he'll go now.) There's also Eric Chavez and not much else. The Brewers and Rays will probably still be looking for a first baseman, so it'll be a small-market fight to the death to sign Loney. The trade market is, of course, another possibility.
By the way, Carter Capps is a hard-throwing young reliever with control issues. If the Pirates had really wanted Morrison, it shouldn't have been hard for them to top that offer (with the important caveat that no one knows what the Mariners were thinking). It looks like other teams valued Morrison as they should have.