Pedro Beato was optioned to Triple-A Buffalo after being the primary culprit in Washington's 8-2, 10-inning win Monday night at Citi Field.

The Mets needed a roster spot for the activation of Matt Harvey, who will start Thursday in Arizona.

Sandy Alderson had acknowledged pregame that a position player was expected to be demoted to open the spot for Harvey, since the Mets were carrying an extra bench player. And there were clear indications Lucas Duda was on the verge of being sent to Buffalo. But Beato's performance clearly changed the thinking.

The Mets became only the third team since 1900 to lose consecutive extra-inning games by five or more runs, according to the Elias Sports Bureau. They joined the 1994 California Angels and the 1973 Houston Astros.

Terry Collins said Josh Thole told him Beato's pitches were right over the middle of the plate. After inheriting a pair of runners, Beato surrendered an RBI single to Bryce Harper, three-run double to Ryan Zimmerman and two-run homer to Michael Morse. He departed having recorded only one out, on a failed sacrifice bunt.

"Those pitches were right over the plate, and they took advantage of it," Beato said.

Beato had uncorked a game-ending wild pitch in the 10th inning in D.C. last Tuesday after inheriting the bases loaded from Byrdak.

Five of the runs in the 10th in the latest defeat were earned, lifting the Mets bullpen ERA to 5.16. The franchise-worst mark came in 1962, at 4.76.

"There's not much you can do except try to put guys in there where you think they're going to get people out," Collins said. "... I went out to the mound and Josh said his balls were just right in the middle of the plate. They're going to get hammered by a good team."