Although the Mets have controlled the season series against the Phillies, the first three games of the four-game set that concludes Monday have each been decided by one run.
Climbing the Citizens Bank Park hill for the Phillies will be rookie David Buchanan, who, with Cliff Lee shut down and Kyle Kendrick a free agent after the season, has an opportunity to make a case for a spot in next year's rotation.
The right-hander was optioned to Triple-A Lehigh in July after his first 10 Major League starts. He has a streak of three straight quality starts dating to July 5. In that span, he owns a 3.26 ERA and a 2-1 record, with opponents hitting .257 against him.
In his last outing Wednesday, he allowed three runs on nine hits and struck out five in 6 1/3 innings. He also picked up his first career hit, RBI and run scored in the victory.
Buchanan, a Phillies 2010 signee who would have been a Met if he had signed with New York after the organization drafted him in 2009, will oppose veteran southpaw Jon Niese.
Niese returned from the disabled list in mid-July, and is 0-4 with a 5.76 ERA since the All-Star break. He recorded his fourth consecutive loss Wednesday after yielding six earned runs, eight hits and two walks in a six-inning outing against the Nationals.
Late-inning jams stung Niese in his two most recent starts. He allowed three runs in the sixth inning Wednesday and three runs in the seventh inning against the Nationals on Aug. 1. This year, Niese has a combined 5.88 ERA (17 earned runs in 26 innings) across the sixth and seventh frames.
"It's easy to talk about the should've-would've-could've when you're struggling," Niese said Wednesday. "I'm at the point now where my stuff's back. My arm feels great. But I'm not very consistent hitting my spots. I've just had a couple bad innings and that's what's cost us."
Niese is 7-6 with a 3.03 ERA in 18 career starts against the Phillies.
Mets: Mejia blows third save
Closer Jenrry Mejia, who was unavailable Saturday following two appearances in which he dealt with right calf tightness, made his third appearance in four games Sunday. With the Mets leading by a run in the ninth, he was in line to collect his 18th save since being moved to the bullpen May 12.
Instead, he allowed a double and a game-tying single to erase starter Zack Wheeler from the game's decision. It was just the third time this year that Mejia blew a save.
With two outs and runners on first and second, Mejia's 26th pitch of the inning was pulled just fair down the first-base line by Ryan Howard. That scored Marlon Byrd with the winning run and kept the teams from playing a second straight extra-inning affair.
Before allowing two runs Sunday, Mejia had yielded three earned runs in his last 19 innings (1.42 ERA) while striking out 23.
Phillies: NL East a challenge
Philadelphia began the season 9-5 over its first 14 games against National League East foes, but the club has lost 27 of 41 divisional games since May 11. The Phillies' 23-32 intra-division record is the worst in the NL East.
The last time the Phils won a series against a divisional opponent was when they swept the Braves from June 16-18.
A win Monday would secure Philadelphia's third series tie in its last seven sets against the East.
• The top three active home run leaders against the Mets are all Phillies. Howard leads with 40, Chase Utley has 33 and Jimmy Rollins has 30.
• Saturday night's 11-inning game was the sixth time the Phillies and Mets have played extra innings this season, tying a Mets franchise record set in 1985 against the Cardinals for the most in one season against one team, according to Elias Sports Bureau.
• The Mets are 10-5 in their last 15 games vs. NL East teams.
Maria Torres is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.