Jon Niese doesn’t expect to miss more than two starts before rejoining the Mets’ rotation.

A person close to the injured lefty told The Post that Niese’s right hamstring has recovered nicely since Sunday, when he gingerly walked off the mound in Florida.

Wanting to play it safe, the Mets placed Niese on the 15-day disabled list, retroactive to Monday, clearing roster space for knuckleballer R.A. Dickey to start against the Nationals .

Niese underwent an MRI exam Monday in New York and hasn’t needed further testing.

“He feels a lot better,” Niese’s friend said. “He’d like to be back out there pitching [Friday], but he also understands this is a marathon and the team needs him for the whole season. He is fine with the DL decision.”

Niese was attempting to field a Gaby Sanchez bunt in the third inning against the Marlins on Sunday, when he planted too hard on his back leg while making an errant throw. The lefty threw one pitch to Hanley Ramirez then signaled for help.

The Mets want to be cautious given that Niese tore his right hamstring tendon last Aug. 6 and had subsequent season-ending surgery.

If Niese returns as expected, the Mets would have Dickey and Friday’s starter, Hisanori Takahashi, competing for one spot in the rotation.

Jerry Manuel said it’s possible Dickey could start the series opener against the Phillies at Citi Field on Tuesday. But Monday’s off day gives the manager the option of skipping that spot in the rotation.

Because Manuel has never managed a knuckleballer, he was planning to rely on results more than stuff when trying to evaluate Dickey.

“I will have to see the response of the opposition – how they react to it and what type of hits they are getting to see if somebody really has a good feel of hitting a knuckleball,” Manuel said. “It’s a first for me.”