NEW YORK -- The Mets don’t yet know who they’ll play in the National League Championship Series. They do know it will start on Sunday. And they’re pretty certain Jeff McNeil will be part of it.

McNeil, who has been sidelined since Sept. 6 due to a fractured right wrist, expects to be ready to go when the NLCS begins in either Los Angeles or San Diego. The team successfully petitioned Major League Baseball to let him play in the Arizona Fall League on Friday and Saturday.

So long as McNeil comes out of those games without issue, both he and manager Carlos Mendoza said, the Mets will activate him when they release their NLCS roster on Sunday.

“He’s got to get at-bats, he’s got to play two games, and yeah, we have some tough decisions to make,” Mendoza said. “But yeah, there’s a good chance -- there’s a really good chance -- he’s on the active roster.”

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There is precedent for a big league player appearing in the AFL, which is typically a showcase for prospects without any MLB service time. Most notably, Kyle Schwarber did so for the Cubs in 2016 after missing nearly the entire regular season due to a knee injury. He made it back in time for the World Series. In 2022, Tyler O’Neill went to the AFL as well, though he never wound up playing for the Cardinals that postseason.

But McNeil, who played for the Salt River Rafters as a little-known prospect in 2015, may have the longest gap -- nine years -- between AFL appearances in the league’s history.

McNeil will fly to Phoenix on Thursday and play both second base and right field in the AFL. While the Mets want him to receive as many at-bats as possible in two days, they are mostly concerned with how his body responds to playing full games on the field.

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McNeil’s activation will likely come at the expense of rookie Luisangel Acuña, who has played only sparingly this postseason, and mostly as a defensive replacement. It remains to be seen how Mendoza will deploy McNeil, given the success of Jose Iglesias at second base.

Those two could fall into something of a platoon, though the Mets’ insistence on having McNeil play right field in the AFL suggests he could get reps there as well.

Following a disappointing first half, McNeil turned his season around after the All-Star break, slashing .289/.376/.547 with seven home runs in 41 games until he broke his hand on a hit-by-pitch on Sept. 6.

Unlike most other injured players, McNeil missed the Mets’ final road trip and Wild Card Series win over the Brewers because he flew home to California for the birth of his second child. He returned to the team last weekend and immediately began ramping up baseball activities.

On Wednesday night, following the Mets’ 4-1 win over the Phillies in Game 4 of the NL Division Series, McNeil participated in a champagne celebration for the first time.

“I’m so happy that Jeff got to experience this, because he didn’t get a champagne shower on the road,” said longtime teammate Pete Alonso. “But to be able to champagne shower at home, this is the first time Citi Field got christened by beer and champagne [after a Mets series win].

“So this is really a special moment.”