PORT ST. LUCIE — Mike Pelfrey will get his first start in over a week here tomorrow when the Mets resume Grapefruit League play against the Nationals in a 1:10 p.m. game that will not be televised. Pelfrey has been sidelined by a strained muscle in his lower left leg. The Mets also have Livan Hernandez scheduled to pitch as he vies for the No. 5 starter role. More in tomorrow’s print edition of The Post …