Over at FanGraphs, I ran all through the numbers and found that trading Ike Davis is probably a matter of a win -- Lucas Duda can probably come within a win of Davis' work at first base, so the Mets need to find a win of an upgrade somewhere else on the diamond in order for this to make present-value sense. With the financial situation of the Mets as it is, and the flagging attendance, along with existence of the second wild card, it seems the team will continue to try and field teams that are at least somewhat competitive in the short-term.
So what team that needs a first baseman can give the Mets a present-value one-win upgrade elsewhere on the diamond? That seems like an answerable question.
First, the teams that need first basemen. The Indians got the least from their first basemen in baseball. The Phillies have gotten fewer WAR than anyone other than them, but they have some dude for the position, and he's getting paid. The Mariners need a first baseman. The Astros need everything, but they do have a decent first base prospect in Jonathan Singleton. The Marlins can probably move Logan Morrison over to first and be fine. The Rangers could be an interesting play, but they have a lefty firstbaseman in Mitch Moreland who isn't much worse than Ike Davis, at least against righties (109 wRC+ to Davis' 132 wRC+ vs RHP, though, hmm). Let's leave them on the list. The Rays have an opening and a need once Carlos Pena leaves. The Giants with Brandon Belt are probably out, but on the periphery. The Red Sox, with Adrian Gonzalez gone, are a definite possibility.
So, that's the Indians, Mariners, Rays and Red Sox as the best fits.
Now, where can they upgrade the Mets' current situation by a win or more without overpaying for Davis? Easy answer -- catcher or the corner outfield. So, if they can get cheap three-win corner outfielder (the Mets have gotten 2.4 wins from right and 2.7 from left so far this year) or a cheap two-win catcher, then you have yourself a deal. Ike Davis also has three years of control left, so that's an input.
What can the Indians, Mariners, Rays or Red Sox offer?
The two names that leap off the Indians roster page are Shin-Soo Choo and Michael Brantley. Both have been worth 2.5 wins and would likely be a win's worth of upgrade. Here's the problem: Brantley -- who is under control for a year longer than Davis -- doesn't replace the power that Ike has. He also gets much of his value from defense in the corner outfield, which is something the Mets could use, but might not be something they value as much. Brantley is also likely the Indian's center-field solution next year. If you look past Choo's poor defensive numbers this season, he's definitely an upgrade for the Mets, and possibly as much as a four-win true-talent player. But he's only under control for another year.
How about the Rays? They won't trade their B.J. Upton replacement (Desmond Jennings) most likely, and if they traded Matt Joyce (2.0 WAR this season), they'd be left trying to fill two outfield holes with Brandon Guyer and the free agent market place. And Ike Davis is not leaving town for one of their young catchers. This doesn't seem likely -- and trading with the Rays has seemingly become impossible in recent times anyway.
The Mariners want offense. The Mets need offense. Unsure how this would work out. Even if Jesus Montero was on the table, and I doubt he is.
So we come to the Red Sox. They need a first baseman, and they like to be competitive every year. They trade often. They have outfielders and catchers. Well... they did. With Cody Ross heading to free agency, and Carl Crawford gone, their only lock for next year is Jacoby Ellsbury. And for all his health issues, he was almost a ten-win player last year and isn't likely to be traded for a first baseman. They do have two interesting catchers. Jarrod Saltalamacchia would be at least a win upgrade over Josh Thole -- but he's only under control for another year.
If they focus on getting prospects for Davis, it's a whole new ball game, but it also means that they'll be trading away three 2013 wins without getting any back. That seems like an unlikely proposition. If it did happen, it might be a package based on Ryan Lavarnway and Ryan Kalish from Boston that would leap to the front of the line. At least they're ready to contribute, and in positions of need.
If they try to get a win-now player that can upgrade them at a position of need, barring some sort of Jesus-based miracle trade or the involvement of a dark-horse team like the Rangers, the Mets might need to settle for packages headed up by Shin-Soo Choo or Jarrod Saltalamacchia -- with prospects coming back to help defray the value of the extra years of control Davis would offer his new team. Given this state of the market for first basemen, Davis' current season, and these sorts of possible returns, it seems that a trade itself is unlikely.