WHAT IT MEANS: Johan Santana flopped in his return from the disabled list, matching the shortest start of his career while being charged with eight runs.

The Mets dropped to six games under .500 for the first time this season with Saturday’s 9-3 loss to the Braves.

Terry Collins pulled Santana after the southpaw had recorded only four outs. Santana, who had never had a start of less than three innings before undergoing Sept. 14, 2010, shoulder surgery, now has twice lasted just 1 1/3 innings against Atlanta this season. He was knocked out at Turner Field on April 17 also after recording only four outs.

Former hitting coach Howard Johnson speculated via Twitter during Friday’s game: “They'll never admit it but Johan is not healthy and hasn't been for awhile. I think arm. More of a hunch. When you're healthy it’s effortless -- don't feel like you have to overthrow or work as hard to get the velocity. I know through my own experience, plus seen a lot of players go through it and it's very difficult to deal with.”

Jeremy Hefner, spared a demotion when Garrett Olson was designated for assignment to clear the roster spot for Santana’s activation from the DL, served up a three-run homer to Freddie Freeman. That long ball allowed a pair of runners inherited from Santana to score as the Braves grabbed a 9-0 lead. Freeman’s shot cleared the “Home Run Apple” in dead-center.

Santana’s final line: 1.1 IP, 8 H, 8 R, 8 ER, 1 BB, 2 K.

Santana became only the third pitcher in Mets history to allow six-plus runs in four straight starts, joining Al Leiter (1999) and Pedro Astacio (2002). In Santana’s four starts, he has allowed 27 earned runs, 36 hits and six walks in 14 innings.

In the nine starts since his no-hitter, Santana has a 7.98 ERA and .328 opponent batting average.

The eight runs allowed by Santana matched the third-most surrendered in his career. He allowed 10 runs against the Phillies in 2010 and nine against the Yankees in 2009.

Hefner contributed 3 2/3 innings and did not surrender any additional damage beyond the Freeman homer. Manny Acosta added two scoreless innings.

Kris Medlen limited the Mets to one run and five hits in 6 1/3 innings.

WHAT’S NEXT: The series concludes on ESPN at 8:05 p.m. Sunday with Jon Niese (8-6, 3.82 ERA) opposing right-hander Ben Sheets (4-1, 1.41).