The veteran lefty most likely will not be on the move over the deadline unless a big bat comes back in return.
Since he entered the major leagues back in 2008, Jonathon Niese has been stellar if not entirely durable, registering a 3.87 ERA with a 3.60 xFIP, 7.25 K/9 and 2.77 BB/9. Additionally, his stats this season seem to fall mostly in line with his career numbers, as he has posted a 3.13 ERA with a 3.76 xFIP, 6.59 K/9 and 2.47 BB/9. However, also in line with his career norms, Niese has spent time on the DL this season with injuries to his left arm. The injuries to Niese's throwing arm become even more unsettling when one realizes that Niese has lost almost 2 mph on his fastball since 2012, with his velocity down from 90.5 to 88.9. So, while the veteran lefty has been very dependable this season, his stock may not be as high as it once was, especially considering that he only recently returned from the disabled list, a couple of weeks before the upcoming trade deadline.
Even with his faults, however, Niese has been the subject of endless trade rumors over the last couple of seasons, often mentioned as a player who could bring back a couple of good prospects. With the Mets entering the win-now mode of their multi-year long plan, Niese could net the team the big bat they have been looking for. The Mets are known to have interest in both Rockies stars, Troy Tulowitzki and Carlos Gonzalez, and surely will be interested in Marlins slugger Giancarlo Stanton when Jeffrey Loria realizes how much he alienated his star player with his controversial moves back in 2012 and makes him available.
While Niese no longer appears to be available for prospects only due to different organizational needs, Sandy Alderson and Co. seem very likely to jump at the opportunity to deal the lefty and others for a proven bat. While big-name players are unlikely to move over the trade deadline, it is not entirely impossible.
Availability
Niese is most likely very available, even if the team won't say it publicly. Regarding any hypothetical Rockies trade, the Rockies figure to want both major league-ready players and prospects in return, in order to not alienate their fan base by completely rebuilding. When choosing between which veteran starter to flip, Niese or right-hander Dillon Gee, the Mets figure to choose Niese because of a higher value to other teams and a higher paycheck.
The Market
When the Mets do make Niese available, potentially all thirty teams in baseball will come calling. However, considering that the Mets will no longer be looking for prospects in return, not many team will fit as potential trade partners. Instead, teams with big bats available will probably be the only ones who have extensive conversations with Sandy Alderson about Niese.
The Return
That elusive big bat. While it's still unlikely that the Mets are able to land one of the market's big bats due to price tag and competition, don't expect Niese to be shipped away from New York for anything less than a middle-of-the-order thumper. While trading Niese by himself won't be enough get the Mets the type of player they are looking for, he could be a big piece of a trade package in a franchise-altering move.