PHILADELPHIA -- Before arriving at Citizens Bank Park this weekend, Mickey Callaway and his coaches met to discuss their pregame procedures in light of last week's lineup card snafu, as well as their overall processes as a team. Self-evaluating, Callaway tweaked things here and there in hopes of helping the Mets snap out of their May malaise.
But when it came time to make a significant in-game decision, Callaway pulled the wrong string. Allowing Paul Sewald to face Nick Williams instead of lefty specialist Jerry Blevins in a one-run game Sunday, Callaway watched from the dugout -- and Blevins, mouth agape from the bullpen -- as Williams hit a go-ahead, three-run homer in the Mets' 4-2 loss to the Phillies.
"You always go back and think about what would have been," Callaway said. "But if you live your life with what-would-have-beens, you wouldn't be a very happy person. We make the decisions we make, and then we move on."
• deGrom's day ends after 45-pitch scoreless 1st

For the Mets, that meant heading home after a 2-3 road trip through Cincinnati and Philadelphia, with nine losses in their past 11 games.
They did not fall behind Sunday until the sixth, when Sewald, pitching a second inning, allowed a leadoff double and a one-out walk. With two outs, Williams strode to the plate as a pinch-hitter, creating an obvious situation for Blevins; though Sewald has shown marked improvement against left-handed hitters this season thanks to a new changeup grip and an increased emphasis on the pitch, he cannot match Blevins' years-long track record of dominating lefties.
Yet with Blevins warm in the bullpen, Callaway stuck with Sewald, who left a slider just high enough in the zone for Williams to bash it a projected 400 feet over the right-field wall, per Statcast™.

"I'm not looking in the dugout for somebody to take me out, ever," said Sewald, who bemoaned both his pitch selection and location. "I didn't even realize there were guys warming up in the 'pen. For me, it was just that I didn't get it done today."
The Mets had to stretch several of their relievers, including Sewald, after starter Jacob deGrom lasted only one inning, which is why Callaway said he stuck with Sewald. Had Blevins entered and allowed a hit, Callaway added, the Mets would have needed to burn yet another reliever. Instead, Sewald gave up the hit and Blevins never pitched.
"I always want to pitch. … It's my job," Blevins said. "If I'm up and I don't get in, I'm always upset."

Although deGrom did not allow a run, he threw 45 pitches in his return from the disabled list. That, along with a 59-minute rain delay that preceded the game, was enough for the Mets to practice caution with one of their most valuable pitchers.
Entering in relief of deGrom, Robert Gsellman threw three shutout innings, and Yoenis Cespedes led off the top of the sixth with a homer to give the Mets the lead. But Sewald, who threw a scoreless inning in the fifth, could not hold it. Jeurys Familia also allowed an eighth-inning home run to Carlos Santana to give the Phillies a measure of insurance.

MOMENTS THAT MATTERED
While deGrom solidified his reputation of doing his best pitching in the toughest spots, it came at a price. After walking the bases loaded in the first inning, deGrom struck out Rhys Hoskins, induced a forceout at home plate off a Santana grounder then whiffed Maikel Franco to end the inning. But he threw 45 pitches in the process, prompting Callaway to turn to a fresh arm in the second.
"I just couldn't really locate anything," deGrom said. "I felt fine. That's what was frustrating. Warming up, I felt great, and then when I went out there, the first pitch of the game, I missed by four feet."

SOUND SMART
For years, David Wright made Citizens Bank Park his second home, producing some of the best numbers of any visiting player in the ballpark's history. He has since ceded that mantle to Cespedes, who hit his 11th home run in 20 career games in Philadelphia -- the most of any visiting player here since 2015. Cespedes has also driven in 25 runs, scored 20 and slugged .741 at the ballpark. He did his damage this weekend despite playing, in his manager's estimation, at 85 percent with a sore right quadriceps.
"He did a good job," Callaway said. "When he had to run hard, he ran hard. When he went to get a ball in the corner, he ran hard. He hit a homer. He's gutting it out for the team."

ROSTER MOVES
The Mets' roster churning continued before Sunday's game, when they optioned lefty reliever Buddy Baumann to Triple-A Las Vegas to clear roster space for deGrom. Baumann did not pitch in the only game he was active, though he did serve his one-game suspension for taking part in an on-field altercation while with the Padres in April.
After the game, the Mets told first baseman Dominic Smith that he will join Baumann in Las Vegas (the move is not yet official). Smith spent three days with the Mets subbing for outfielder Jay Bruce, who was on paternity leave.
UP NEXT
Using ample off-days to their advantage, the Mets, who skipped Jason Vargas' turn in the rotation, will give the ball to Noah Syndergaard when they return to Citi Field for a 7:10 p.m. ET game Tuesday against the Blue Jays. Syndergaard warmed up prior to the Mets' rainout Saturday in Philadelphia but did not appear in the game. Instead, he'll face the team that drafted him, while the Blue Jays will counter with left-hander Jaime Garcia.