OAKLAND, Calif. — Max Scherzer’s lingering back soreness from his last start has changed the Mets’ pitching plans.

After the Mets’ 3-2 victory over the Athletics on Saturday, manager Buck Showalter said Jose Butto will start the series finale on Sunday.

Scherzer, who had been scheduled to start, has been bumped to Wednesday against the Dodgers.

Scherzer received an MRI exam, which he said showed nothing serious, in an area “south” of his right scapula after a 30-pitch side session on Friday.

Because the Mets were planning to insert a sixth starter into the rotation for this turn through, he decided the best action would be to defer his start a few days.

The Mets’ co-ace said it’s an ailment that he dealt with in 2019 while pitching for the Nationals.

“I respect it, know what it is, and know that if you give it a little rest it just goes away,” Scherzer said. “That is the calculus in the decision making where the conversations were at.”

Butto started one game for the Mets last season, allowing seven earned runs over four innings against the Phillies. The right-hander was recalled from Triple-A Syracuse before the game Saturday.

Scherzer’s discomfort comes as the Mets are awaiting the debut of their other co-ace, Justin Verlander, who started the season on the injured list with a strained teres major muscle near his right armpit.

Showalter decided to insert the sixth starter for this turn in the rotation in large part to give Kodai Senga an extra day of rest between starts.

The manager never officially said which day the extra starter would pitch, but Senga’s turn would have occurred Wednesday.

“I am trending in the right direction, but [the soreness] is not fully gone, so why even introduce risk?” Scherzer said. “If we know we have an open spot, then it’s selfish for me to go try to pitch … around this, when you have that on the table.”

Scherzer, 38, has pitched to a 4.41 ERA in his three starts this season.

In his most recent appearance, he fired five scoreless innings against the Padres, but worked deep into counts and was removed after 97 pitches.

Last season, the Mets lost Scherzer to two stints on the injured list with oblique issues.