MLBTR.com, the Mets aren't actively shopping Jonathon Niese, and despite an earlier report that they were interested in trading him for a package around Rockies outfielder Seth Smith, they have "zero interest" in such a deal according to ESPN's Jerry Crasnick (in these four tweets).
New York would have to be "knocked out" to trade Niese, who is not yet arbitration eligible and owns 286 strikeouts and 106 walks in 331 innings over the past two seasons. His ERA is a pedestrian 4.30 in that time, though his 49.5% groundball rate and advanced metrics like FIP (3.75) and SIERA (3.67) tell a different story.
At the Winter Meetings, we heard that the Mets would be willing to move any player other than David Wright, and several teams showed interest in the 25-year-old Niese, viewing him as a potentially cheaper alternative to Gio Gonzalez. Reports since then say that there have been "no significant talks," however, and Crasnick's strong words suggest that Niese won't be easy to acquire at all.