Mets’ Francisco Alvarez leaves game with back injury….

New York Mets catcher Francisco Alvarez deemed himself OK after he left Friday night’s game against the Milwaukee Brewers in the seventh inning after sliding into third base and indicating obvious pain, grabbing at his back.

The Mets said he exited the game with back spasms. Mets manager Carlos Mendoza said Alvarez was walking around better within 30 minutes and left open the possibility that he could be in the lineup Saturday.

“I feel way better,” Alvarez said after the Mets’ 8-4 loss. “I will see tomorrow how it’s going to feel and if I could play tomorrow.”

For the Mets, that’s a relief.

Mendoza said that initially, things didn’t look so good. Upon reaching third base on a grounder, Alvarez quickly called to the dugout and stayed down on his stomach for a few moments. He then needed to be helped off the field. He walked down the tunnel toward the clubhouse with the support of athletic trainers.

Alvarez said he felt better after coming out of the game and working with the trainers. He said he doesn’t need an MRI.

Before Alvarez’s injury, things had already gone awry for the Mets.

While in the hunt for one of the final two playoff spots in the National League, the Mets played one of their worst games of the season. By the time Alvarez left the game, the Mets had already allowed seven runs, four walks and five stolen bases while playing sloppy defense.

Potentially losing Alvarez with four games left would be a significant blow. After hitting 25 home runs as a rookie last year, Alvarez entered Friday’s game with 11 home runs and a .704 OPS. His bat had just heated up with five home runs in September.

Without Alvarez, the Mets would lean on backup catcher Luis Torrens who has impressed defensively. But after a hot start, Torrens has slowed down offensively. In September, he’s 3-for-16 (.188 batting average). Entering Friday he owned a .699 OPS.