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8/7/2014 7:10 P.M. ET

Tight calf leads to Mejia's exit after 12th

WASHINGTON -- In a game already pushing five hours, the Mets certainly could have used multiple innings out of closer Jenrry Mejia.

Instead, a tight calf forced Mejia out of Thursday's 5-3 loss to the Nationals after a single scoreless inning. The closer does not believe his injury to be anything serious, but he said he cannot be sure until he tests it prior to Friday's series opener in Philadelphia.

"It feels a little bit tight," Mejia said.

Noting that the injury first began vexing him earlier this week, Mejia said he received an in-game massage that reduced his discomfort. But he began feeling it again during his 18-pitch 12th inning on Thursday, forcing him to retreat to the clubhouse after recording the third out. Carlos Torres came on and ultimately gave up Bryce Harper's walk-off homer in the 13th.

Mejia also pitched through a sore back last weekend in New York, and he has a long history of arm issues dating back to 2010. The Mets believe his latest ailment falls toward the less-serious end of the spectrum.

"We'll find out more [Friday]," manager Terry Collins said. "Right now, the trainers don't think it's anything serious. But it was serious enough that he wasn't going to pitch anymore today."

If Mejia is unable to pitch this weekend, Jeurys Familia and Vic Black would be the leading candidates to replace him at closer.

Early homer snaps deGrom's impressive streak

WASHINGTON -- It had been exactly nine weeks since Jacob deGrom last allowed a homer. But as Ian Desmond's two-run shot in the second inning Thursday sailed out of Nationals Park, one of the most impressive statistical oddities of deGrom's breakout season came to an end.

Desmond's homer snapped deGrom's franchise rookie record at 67 1/3 innings -- or the equivalent of more than seven full games -- without a home run.

"It's over with there," deGrom said. "There's nothing you can do about it. You've got to go back out and try to get the next guy out. That was kind of my thought process."

Doing precisely that, deGrom rebounded to allow just one other run over six innings of a no-decision, shaving his ERA back down to 2.87. He remains one of the National League's two top Rookie of the Year Award candidates, alongside Reds outfielder Billy Hamilton.

But the home run ball to Desmond still irked him.

"I was trying to go two-seamer in, but I left it up a little bit," deGrom said. "He just got to it."

Collins unconcerned with Wright's adjustments

WASHINGTON -- Mets manager Terry Collins is downplaying the effects that David Wright's mechanical tinkering may have had on the third baseman's performance to date.

"He's done that since I've been here," Collins said of Wright, who entered Thursday's series finale against the Nationals with just one extra-base hit since the All-Star break. "That's what these guys do here, everybody. They're always looking at something if they go into a little slump."

Collins harkened back to 2012, when Wright hit .351 with 11 home runs before the All-Star break. Hoping to generate even more power in the second half, Wright tinkered with his swing and hit just .258 with 10 home runs after the break.

This year, Collins believes Wright initially adjusted his swing to compensate for the discomfort he was feeling in his sore left shoulder. Now that the shoulder is mostly healed -- Wright continues to insist it's a complete non-factor, despite his struggles since receiving a cortisone shot last month -- Collins believes his third baseman is working to rediscover his old stance and swing.

Pence responds to Mets fans' ribbing

WASHINGTON -- The Mets fans who spent most of last week razzing Giants outfielder Hunter Pence have received their official response.

A group of fans showed up to Citi Field last week bearing signs lightly insulting Pence in some of the most bizarre ways imaginable -- "Hunter Pence cannot parallel park" and "Pence puts ketchup on his hot dogs," for example. The signs kept coming, even after Pence torched Mets pitching for seven RBIs in the series' first three games, and they have since surfaced in cities throughout the country, sometimes in reference to other players.

Pence has now done more than simply respond on the field, posting several pictures of himself acting out those insults.

In one, he is hunched over a book amidst wording that reads, "Hunter Pence returns library books before they're due so others can enjoy them as well." In another, the phrase "Hunter Pence cannot parallel park" reappears above a picture of Pence giving a thumbs-up in a sleek convertible.

Pence has more than 245,000 Twitter followers.

Worth noting

• Collins was incredulous to see former reliever and clubhouse prankster Tim Byrdak at Nationals Park on Thursday, serving as part of WOR's broadcast team.

"Is he with you?" Collins asked play-by-play man Howie Rose upon seeing Byrdak. "You guys will be off the air by the 15th."

• The Mets are reintroducing their "Strikeouts for Savings" promotion, in which the team's strikeout totals will determine ticket discounts for an upcoming series. For every batter the Mets strike out from Friday-Monday, fans will save one percent off regularly-priced tickets for select seats during the team's next homestand from Tuesday through Aug. 18. Discounted tickets will go on sale within one hour of the conclusion of Monday's game in Philadelphia.

Anthony DiComo is a reporter for MLB.com. Follow him on Twitter @AnthonyDicomo. This story was not subject to the approval of Major League Baseball or its clubs.