An adventurous squirrel — and not former utility player Jeff McNeil — was the highlight of the Mets’ evening Wednesday.

Unlike the team, it gave Mets fans something to cheer about.

Robert Stock and the lifeless lineup certainly didn’t.

The journeyman right-hander had very little, and the Mets failed to take advantage of Brewers starter Dustin May leaving after one batter in an ugly 8-1 loss at Citi Field.

In the bottom of the third inning, the crowd began cheering. A squirrel had gotten loose behind home plate.

The cheers turned to groans as the Mets failed to take advantage of a two-on, two-out opportunity when Carson Benge flied out to left field. As the fans were rooting on the squirrel, Bo Bichette fouled a pitch off his foot. He later left the game with a left ankle contusion.

In the top of the following inning, the Brewers put the game away. Brice Turang ripped a three-run homer to make it 7-0. Stock was trying to go for the strikeout but hung a 1-2 slider that Turang crushed.

“It was a pretty risky pitch because it might get a swing and miss, but it’s most likely to give up a home run if he does connect. That’s exactly what happened,” Stock said. “Their good approach forced me to do something I wasn’t comfortable with, and it wound up burning me.”

Milwaukee started the second with six consecutive hits. Stock, who replaced Freddy Peralta in the starting rotation when the veteran was traded to the Rays, hasn’t given the Mets much length.

He lasted only four innings Wednesday and gave up 10 hits and seven earned runs, as his ERA rose to 7.40.

“When you face a team like that, it’s kind of rolling the dice. They’re going to put the ball in play and it’s on you to make your best pitches, and a theme that I’ve noticed for every outing is my velocity has been dipping,” Stock said. “Not because I’m not feeling good, but I think because I’m spending so much time working on throwing strikes. That’s my strongest suit, is I should be able to go out there and throw 98. Tonight I didn’t see any 97.”

In five starts, he has failed to record an out in the sixth inning. This performance was similar to his Aug. 8 start against the Pirates, when he was tattooed for nine hits and eight earned runs in three innings.

Next week, rosters expand by two, and the Mets could opt to replace Stock in the starting rotation with a prospect like Jonah Tong. Interim manager Andy Green said before the game he was unsure of any promotions that could be coming.

He reiterated that stance afterward.

“We just finished up the game right now. We’ll get in there and talk about it as a group, see where our heads are at,” Green said. “He’s had some nice starts for us. This was another one I’m sure he would want back.”

Leading off the game for the Mets, A.J. Ewing drilled a line drive off May’s right shoulder.

May initially tried to stay in but was in obvious pain and, after a few warmup pitches, departed. It was later announced as a right scapula contusion.

It didn’t help the Mets lineup.

Robert Gasser held them to six hits and one run over 5 ¹/₃ innings. His lone hiccup was allowing a Francisco Alvarez run-scoring single in the fourth.