Josh Satin had Ike Davis’ old locker Tuesday. Daniel Murphy had Davis’ old position. And Jordany Valdespin had Murphy’s old position.

Tuesday night, the Mets played their first game since Davis’ demotion to Triple-A, and the absence of the struggling first baseman meant the infield’s right side was different. Manager Terry Collins slid Murphy from second base to first in the 9-2 loss to the Cardinals while awarding Jordany Valdespin the opportunity at second base.

Murphy’s return to first base — his first time playing the position since last Oct. 2 and his first time starting there since last Sept. 4 — didn’t go well. He committed a brutal error on Jon Jay’s fourth-inning grounder, having the ball kick off his glove and then throwing high to Jeremy Hefner covering first. It led to five unearned runs.

“It’s a routine ground ball. I misplayed it,” Murphy said. “There’s no excuse.”

Valdespin fared better, handling second base with no problem and collecting a pair of singles.

How much Murphy will continue to play first base is to be determined. Collins said he wants to play Satin, called up from Triple-A after Davis’ demotion, at times and Murphy might move back and forth.

“He may fluctuate a little bit between first and second,” Collins said. “I know if there’s one guy who can bounce around, it’s him.”

Collins wants to audition Valdespin at second base, “the position [where] he’s most comfortable,” the manager said. With the Mets facing six straight righty starters from the Cardinals and Cubs, Collins said he will give the lefty-swinging Valdespin the six starts.

“I think it’s my time because they want to give me the chance to show I can do my job,” Valdespin said.

Discussing Valdespin on Monday, general manager Sandy Alderson told The Post, “I think we’re inclined to give him an audition at second base. I’m not sure how long that audition will last. We’re pretty familiar with him as a player.”