WASHINGTON -- Right-handed pitcher A.J. Cole, on Wednesday, sat behind home plate wearing street clothes at Triple-A Lehigh Valley as he charted pitches for Triple-A Syracuse.

Two nights later he was here at Nationals Park, starting for first-place Washington in the first game of a four-game weekend set against the New York Mets.

Cole, in his fifth major league start of the year, had the misfortune of going up against right-hander Jacob deGrom. And while Cole pitched well, deGrom was even better, leading the New York Mets to a 4-2 win over the Nationals, even though the visitors lost left fielder Yoenis Cespedes to a hamstring injury.

"I have been working on mechanics still," said deGrom, who dealt with a sore foot as he stepped into a hole in the Nationals Park mound. "I was able to locate; I had a good feel for every pitch."

The win came with a cost. Mets general manager Sandy Alderson said after the game that Cespedes will go on the disabled list and could be lost for the year after he strained his right hamstring while running the bases in the first.

"He will be examined Monday in New York. We will have somebody else in here tomorrow; we will have someone take his spot," Alderson said. "I would say the season is in jeopardy."

DeGrom continued to shine as he gave up one run in 7 2/3 innings and Juan Lagares had two hits and drove in a run.

"He is a competitive guy," Mets manager Terry Collins said of deGrom. "He just went out and competed. He's a special kid."

A Stetson product, deGrom (14-7) allowed five hits while striking out 10 and walking just one.

"A lot of that has to do with deGrom," Washington manager Dusty Baker said of his weak offense.

The Nationals broke up the shutout bid as Adrian Sanchez had an RBI single in the eighth to make it 3-1. Andrew Stevenson doubled with two outs and scored on the hit by Sanchez, which sent deGrom to the showers. Former Washington lefty Jerry Blevins then fanned Daniel Murphy to end the threat.

Lagares drove in a run with a single with two outs in the ninth to make it 4-1.

A.J. Ramos pitched the ninth for his fourth save with the Mets and 24th overall despite allowing a leadoff homer to Adam Lind (two hits) to make it 4-2. Wilmer Difo (two hits) followed with a double but Ramos got the last three outs after pinch-hitter Anthony Rendon nearly hit a game-tying homer that was just foul.

Ramos fanned Stevenson with the bases loaded for the final out.

Matt Reynolds, who entered the game in the first inning for the injured Cespedes, had an RBI single in the eighth off Matt Grace to give the Mets a 2-0 lead. Rookie Dominic Smith had an RBI sacrifice fly later in the eighth to make it 3-0.

Cole (1-4), in his 14th career start in the majors, matched a career high with eight strikeouts. He gave up one run on four hits in six innings with four walks.

"Cole, he threw great after that first inning, and we were lucky to get out of there with just one run because it hit the umpire, and then he got out of that inning with just one run," Baker said.

Said Cole: "I was trying to be a little too perfect too quick. Instead of trying to let them get themselves out, I was trying to get them out with one pitch. I was a little too fine."

The Nationals (76-50) started just one player who was in Opening Day lineup -- former Mets second baseman Murphy. The Mets (56-71), who had lost eight of 10, are just 4-9 against Washington this year. Asdrubal Cabrera was 2-for-5 for New York.

Brandon Nimmo led off the game with a walk, took second on a one-out walk to Cespedes and scored on a single by former Nationals infielder Cabrera to give the Mets a 1-0 lead in the first.

Cespedes left the game minutes later. The slugger was favoring his right leg as he rounded third on a single by Smith. Cespedes touched home and then was helped off the field by an athletic trainer. Since the batted ball by Smith hit the second base umpire, Cespedes had to go back to third base.

Reynolds went to third to run for Cespedes, who went on the disabled list April 28 with a left hamstring strain. Cespedes is hitting .292 with 17 homers and 42 RBIs in 291 at bats.

"This is new for me, for anybody else who has probably ever managed," Collins said of his team's latest injury. "There is no way to really describe it."

NOTES: Washington RHP Max Scherzer (neck), who is on the 10-day disabled list, threw a bullpen session before Friday's game and it appears he could start Sunday night. ... Mets OF Michael Conforto (dislocated left shoulder), who was hurt Thursday, was officially placed on the disabled list Friday and RHP Jeurys Familia came off the 60-day disabled list. ... Washington RHP A.J. Cole was called up from Triple-A Syracuse to start Friday while C Pedro Severino was sent to Syracuse. ... LHP Gio Gonzalez (12-5, 2.39) will face Mets RHP Robert Gsellman (5-5, 5.65) on Saturday. ... The Nationals plane landed about 4:30 a.m. Friday in northern Virginia after a game in Houston on Thursday night.