CHICAGO — Francisco Alvarez’s season could have easily ended in August, but here he is trying to help the Mets reach the postseason for a second straight year.

It’s been a roller coaster of a season for the 23-year-old catcher, between injuries that have twice sent him to the injured list and midseason underperformance that led to his demotion to Triple-A Syracuse.

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Now, in their most important games, the Mets are receiving the best of Alvarez, who delivered a tiebreaking two-run homer in the eighth inning on Tuesday that helped his team beat the Cubs and reclaim the lead for the National League’s third and final wild card.

He entered Wednesday at Wrigley Field with a .781 OPS for September that included three homers. This after he sprained a ligament in his right thumb diving into second base on Aug. 17 — necessitating surgery that has been deferred — and breaking his left pinkie when he was drilled by a pitch on his subsequent minor league rehab assignment.