After Curtis Granderson led off the game with a home run, the Mets managed only two harmless singles in seven innings against Dan Haren during a 6-2 loss Friday night to the Los Angeles Dodgers. The lack of offense didn't make things any easier for Jonathon Niese, whose teammates tied a season-high with four errors. The unearned runs were the result of a throwing error by shortstop Wilmer Flores on a routine grounder by Adrian Gonzalez. The Mets made two more miscues in the eighth, one by third baseman David Wright on a hard grounder by pinch-hitter Andre Ethier, the other by first baseman Lucas Duda on a foul pop by Puig. The Dodgers got their first two batters on in the third inning before Haren bunted into a double play started by Niese. Carlos Torres relieved Niese, and Matt Kemp greeted him with a two-run double to make it 5-1. [...] Mets relievers had stranded 132 of 166 inherited runners (79.5 percent), the best in the majors. Closer Jenrry Mejia, who was held back from a save situation Wednesday at Oakland because of a sore back, was the first Mets player out on the field to do running and was available if needed, Collins said. Rookie Jacob deGrom (6-5, 2.87 ERA) will be reinstated from the disabled list and make his first start since Aug.