NEW YORK -- If all goes according to plan, Robert Gsellman eventually will lengthen the New York Mets' bullpen. On Monday afternoon, he helped spare the overworked relief corps.

Gsellman enjoyed his best game of the season both on the mound and at the plate, posting a victory by tossing seven strong innings and chipping in with two RBIs as the Mets beat the Milwaukee Brewers 4-2 at Citi Field.

Gsellman (3-3) allowed two runs (one earned), three hits and two walks while striking out five. His outing marked just the 10th time this season a Mets starter threw at least seven innings.

The inability of starters to work deep into games has taxed the New York bullpen, which entered Monday with the fifth-highest ERA (4.90) in baseball.

"Certainly he rose up and got us where we needed to get to," Mets manager Terry Collins said.

He also likely moved one step closer to taking up permanent residence in the bullpen. Mets general manager Sandy Alderson said before the game that injured pitchers Seth Lugo and Steven Matz will each make one more rehab start before they are ready to return to the major league rotation.

Assuming those starts go off without a hitch -- no sure thing considering the Mets' general bad luck with injuries and the fact both Lugo and Matz are rehabbing elbow injuries -- they would be ready to replace Gsellman and current fifth starter Tyler Pill during a road trip that begins June 6.

"It's still pitching," Gsellman said of a possible relocation to the bullpen. "I enjoy pitching so much that I really don't care."

His effort Monday provided more evidence to Collins and the Mets that Gsellman can help out in either capacity. Gsellman looked like a potential bridge reliever for a beleaguered bullpen earlier this month, when his turn was skipped and he allowed one run in three innings during two relief outings.

But even if Lugo and Matz return and remain healthy, Gsellman likely will be needed in the rotation at some point down the stretch, especially with Zack Wheeler on pace to throw 162 innings after missing the previous two seasons because of Tommy John surgery.

"I know what Sandy said today about the possibility of him going to the bullpen, and that's going to be the case when we get those other guys back," Collins said. "We go down the road, you never know where Zach's going to be, innings-wise. And you look way down the road, this kid's going to be a quality starter in this league, in my opinion."

Gsellman (3-3) and losing pitcher Matt Garza (2-2) matched zeros until the fifth. The Brewers scored an unearned run thanks to shortstop Asdrubal Cabrera's misplay of a leadoff grounder by Jonathan Villar, who advanced around the bases on a single by Orlando Arcia and a bunt by Garza before scoring on a groundout by Keon Broxton.

The Mets immediately responded with three runs in the bottom of the fifth. Cabrera and Wilmer Flores led off with singles before Rene Rivera doubled home Cabrera. Gsellman's sacrifice fly to right scored Flores with the go-ahead run, and Rivera raced home on Michael Conforto's double.

"Come back with three runs, it was huge for (Gsellman) and for us," Rivera said.

Domingo Santana pulled the Brewers within 3-2 with a homer in the top of the sixth, but the Mets answered again in their half of the inning. New York loaded the bases against Garza and Rob Scahill before Gsellman worked a bases-loaded walk. Gsellman entered Monday with just one RBI in 21 career games.

"Too bad I didn't get a hit, but still got a couple RBIs and helped out the team, finally, in the box," said a grinning Gsellman, who couldn't swing as a rookie last season because of a left shoulder injury.

Paul Sewald threw a perfect eighth inning and Addison Reed posted his seventh save despite allowing two hits in a scoreless ninth for the Mets (22-27), who have won two straight and three of four.

Santana was the only player with two hits for the Brewers (27-24), who have lost six of eight.

"We had three hits going into the ninth inning, so there was not much happening today," manager Craig Counsell said of the Brewers, who entered Monday with the fourth-most runs in the National League.

Garza allowed four runs, seven hits and two walks while striking out four in 5 2/3 innings.

"Gsellman threw a hell of a game," Garza said. "I had that fifth inning where they kept finding holes, a couple of balls that they hit well -- not like screaming liners, just enough to get over the infield -- and (they) piece a couple more together and that's a big inning."

NOTES: The Mets improved to 26-30 on Memorial Day, and the Brewers fell to 14-30. ... Mets rookie RHP Tyler Pill will make his first major league start Tuesday night against Milwaukee RHP Zach Davies. ... Brewers LF Eric Thames returned to the lineup but went 0-for-3 with a walk. He is 0-for-15 dating to Friday.