PHILADELPHIA — Francisco Lindor has been a shell of himself since returning from the injured list, but Sunday he was the whole player.

The Mets shortstop homered in his first plate appearance and didn’t stop until he had reached base five times in his team’s 6-1 victory over the Phillies at Citizens Bank Park.

Lindor began the day with a .594 OPS since his return from the IL on June 24 (he missed two months with a calf strain).

His defensive play has been just as shaky.

So, are the Mets about to receive a dose of the Lindor who has been a key figure in this lineup since 2021?

“I am extremely confident, and there’s no other option,” Lindor said when asked about returning to his All-Star level. “I have to play to a higher standard. I have to play to the level that the organization wants me and I have to play to the level that I expect myself to be.”

Lindor delivered a 3-for-3 performance with three RBIs from the cleanup spot.

He also walked twice, allowing him to reach base five times in a game for the fifth time in his career.

“I’m putting in the work, and the coaching staff here is helping me a lot,” Lindor said. “We have three hitting coaches and they are all sending me videos and all putting in the time. And [bench coach] Kai [Correa], we all know Kai doesn’t stop.”

Lindor committed a throwing error a day earlier.

Last Sunday he failed to turn a potential game-ending double play on a routine grounder, costing the Mets a victory.

Correa, who oversees the team’s defense, told The Post that Lindor is still trying to catch up from the time he’s lost this season.

Before his calf injury, Lindor missed most of spring training due to hamate bone surgery.

“The biggest thing for him is he’s trying to close the gap on the lack of a normal offseason, the lack of a normal spring training,” Correa said. “The multiple serious issues, injuries, consecutively, without continuous play or a rehab assignment. Some of the things you see are mental mistakes that manifest as physical mistakes. It comes from the lack of game flow, where he’s out there and not doing things without thought.”

The Mets can only hope to receive a steady flow of production from Lindor as they attempt to avoid finishing as a complete embarrassment.

“We know who [Lindor] is and he has a long track record of being really good,” interim manager Andy Green said. “The day before the All-Star break, that ended up being a tough day [on the botched double play], but he was swinging the bat really well, and made a ton of good plays that day. It’s good to see him come out, enjoy playing baseball, play it really well and lead us to a win.”