Stone-faced and stoic, his words coated with frustration, Mets ace Matt Harvey refused to sugarcoat what has been the most difficult stretch of his career.

"Extremely bad," Harvey said Wednesday night with the sting still fresh from his 8-5 thrashing by the Giants.

The Mets expected a few speed bumps, of course. Nobody escapes Tommy John surgery without a paying a toll. But after a promising beginning, Harvey's swoon has stretched over four starts in which he has posted a 7.20 ERA.

"It's all new territory," manager Terry Collins said.

In six innings, Harvey (6-4) set a career worst in home runs (three), equaled a career worst in runs (seven) and established a career low in strikeouts (two).

Harvey, 26, again insisted that he feels fine physically. He scoffed at the notion of enduring the type of hangover associated with the surgery.

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"I'm not going to use that as an excuse," he said. "Just a terrible performance."

Despite the Mets' desire to carefully manage his innings, though, Harvey has exhibited some of the classic signs associated with life after Tommy John surgery. In particular, he has fought a losing battle against his command.

"Right now, I'm just not executing with anything," said Harvey, who has allowed 12 homers this season after allowing that number in 2012-13 combined.

The Mets (31-29) dipped a half-game behind the NL East-leading Nationals, though their day began with promise.

One night after being no-hit for the seventh time in franchise history, the Mets activated catcher Travis d'Arnaud from the disabled list.

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"I've had a smile on my face all day today," said d'Arnaud, whose promotion was expedited with catcher Kevin Plawecki still battling dizziness.

Collins said reliever Bobby Parnell and infielder Dilson Herrera also remain on track to be activated, though their return might not come for another day or two.

The Mets played shorthanded Wednesday night, leaving themselves without a reserve infielder when they demoted Danny Muno to Triple-A Las Vegas to make room for d'Arnaud, who went 1-for-4.

They handed Harvey a two-run lead against Tim Hudson. Wilmer Flores delivered a tying two-run single in the first, Eric Campbell laced a two-out single to give the Mets a 3-2 lead in the fourth and Lucas Duda snapped an 0-for-16 skid with an RBI single in the fifth that made it 4-2.

Harvey, meanwhile, appeared to settle in after Joe Panik tagged him for a two-run homer in the first. But he came unraveled in the sixth as the Giants scored five runs.

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Even though the radar gun flashed 99 mph, Brandon Belt and Justin Maxwell homered and Buster Posey ripped a two-run double. The outstanding velocity provided little cover for Harvey, who was pulled at 100 pitches.

Much of the damage came on two-strike counts, when Harvey typically dominates.

"He left balls in the middle of the plate," Collins said. "With his stuff, you don't get hit hard unless he's over the plate."

The downturn has come at a time when the Mets tore up their plans for a six-man rotation, partly to get Harvey on the field more often. Of course, the Mets did not envision this version of their ace.

Said Harvey: "There's a lot of work that needs to be done."

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Draft concludes.The final day of the amateur draft took on a local flavor for the Mets, who chose Floral Park's Thomas Hackimer in the 15th round. The righthander went 4-1 with a 1.92 ERA and set the St. John's record with 15 saves.