NEW YORK -- With Kodai Senga likely out for the rest of the regular season because of a high-grade left calf strain, the Mets need Tylor Megill to be consistent on the mound. It’s safe to say Megill will replace Senga in the rotation.

After spending almost a month with Triple-A Syracuse, Megill returned to a Major League mound for the first time since June 29 and he gave New York length, but the long ball ended up hurting him in a 4-0 loss to the Braves on Saturday at Citi Field. The Mets find themselves a half-game behind the Braves and Padres for the top spot in the National League Wild Card race.

Megill was lights-out in the early going, retiring the first 11 hitters he faced, but he had a tough time getting that third out in the fourth inning. Marcell Ozuna and Matt Olson hit back-to-back home runs to give Atlanta a 2-0 lead.

An inning later, Braves catcher Sean Murphy scored the third run of the game on a single by Orlando Arcia. Megill settled down until the seventh, when he allowed a leadoff home run to Eddie Rosario and then left the game after walking Murphy.

“Obviously, the long ball got him, but I thought he was OK,” Mets manager Carlos Mendoza said. “The first three innings he was really good. I thought the fastball was good. … He went back out there for the seventh. We needed length out of him, obviously. I thought he was fine.”

Megill added a sinker to his repertoire -- learning to throw it during his time at Syracuse -- and felt he was able to throw his slider with consistency. The biggest thing he did in the Minors was get ahead of hitters, which he did in the first three innings Saturday.

“I need to get ahead with the heater, use sliders, and everything opens up if I’m ahead. I thought I did that really well today,” Megill said. “Later in the game, I was getting behind with the sinker, but I managed to get back into [good counts]. Overall, I didn’t think it was terrible. You just tip your cap on the home runs. I haven’t gone into the seventh for a while. The majority [of games have been] five innings or even less.”

It was the type of day where Megill needed to be perfect on the mound because Braves right-hander Spencer Schwellenbach had his best start of the season, pitching seven scoreless innings while allowing just two hits and striking out a career-high 11 batters. New York had runners in scoring position twice against him, but they were left stranded.

Schwellenbach’s four-seam fastball touched a season-high 98.3 mph and averaged 96.8 mph throughout the game. His four-seamer hadn’t averaged higher than 96.2 mph (June 5 at Boston) during any of his previous nine starts.

“I think the slider being what it was today allowed my fastball to be even better,” Schwellenbach said. “I was able to keep them thinking a slider was coming and then I could throw a fastball by them. That worked well today.”

Mendoza came away impressed with what Schwellenbach did on the mound.

“Man, he was on. He was pretty tough,” Mendoza said. “The slider was really good, but then [he had] that cutter at 94, 95 to go with some type of [sinker] at 97 when he needed for a pretty tough at-bat, especially against some of the righties. He was on today. He has a pretty good arm.”