Here's something a little scary to consider: Daniel Murphy is the second longest tenured player on the Mets' active 25-man roster behind David Wright. He and Wright are also the last vestiges of the Mets' last competitive team in 2008. So Daniel Murphy has been around for a while and we've seen him grow from prospect to "left fielder" to man without a position, and finally to starting second baseman
Murphy is now 28 years old and he makes $2.925 million this season. He'll be arbitration eligible in 2014 and 2015, after which he can become a free agent. We all know how streaky Murphy is at the plate and he's in the midst of one of those cold streaks at the moment, but for the season, his line sits at .271/.309/.398 to go along with 6 home runs, 20 doubles, a .308 wOBA and a slightly below average 97 wRC+ (where league average is 100). They're not overwhelming numbers but a typical Murphy hot streak should prop that up a bit. Even so, a league average offensive second baseman is useful, especially when he adds defensive value. And that's the most surprising thing about Murphy's season: UZR rates him at +5.1 at second base, while Defensive Runs Saved places him at -2 runs, and that seems to pass the eye test.
Availability
As the Mets' only other credible starting position player at the moment after David Wright, they should be in no rush to give Murphy away. That being said, it certainly wouldn't be a shock to see him dealt if the Mets got a worthy return, perhaps in the form of an outfielder. That just may be more likely in the offseason, though. Murphy is starting to get more expensive and at 28, his upside is likely somewhat limited. Beyond that, the Mets have 21-year old infielder Wilmer Flores knocking on the door at Triple-A Las Vegas and he likely has more upside at the plate than Murphy, though defensively he's a question mark.
The Trade Market
A number of competing teams could be in the market for an upgrade at second base. The Athletics have been starting Eric Sogard, who's been pretty below average. The Blue Jays have gotten little to nothing out of Maicer Izturis and Emilio Bonifacio. The Royals recently turned second base over to forgotten prospect Johnny Giavotella but with Dayton Moore's job potentially on the line, they could probably use an upgrade there. And the Dodgers have gotten little productivity out of both second and third base all season and the NL West is certainly winnable.
The Return
In order for a deal to make sense, the Mets would likely prefer to get a major leaguer or at least a prospect who's very near to major league ready in exchange for Murphy. Considering how dire their offensive situation already is at the big league level, the Mets probably shouldn't gamble on a prospect who is really far away in this scenario. Looking at some of those teams, the A's have outfield prospects Michael Choice and Grant Green sitting at Triple-A Sacramento. The Blue Jays still have center field prospect Anthony Gose, though he's had a rough year at Triple-A Buffalo. And finally, the Dodgers have a guy at Double-A who plays a little outfield that the Amazin' Avenue commentariat may be familiar with. I believe his name is Joc Pederson. Ringing any bells?