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Old-Timers’ Day is mostly for the fans, who enjoy seeing the stars of yesterday play once more.

The stars of yesterday also make the most of being able to don the pinstripes once more.

And there could be benefits for the current Yankees, too — like a struggling, once-dominant closer hearing a bit of advice from the greatest closer of all time.

Mariano Rivera was planning on talking with Devin Williams on Saturday, Rivera said before taking part in the alumni game in The Bronx.

He did not want to reveal his precise message, but he was intent on delivering one.

Rivera — the first and only unanimously voted Hall of Famer and unquestionably the best reliever ever — did not have a ton of struggles through 19 seasons, but he still learned how to handle the adversity that comes with the game and comes with the closer role.

“Forget about it,” Rivera said about overcoming struggles such as a blown save. “You can’t do nothing about it. What’s done is done. Move on and be confident. You have to be confident in yourself. If you’re not confident in yourself, why are you playing the sport?”

A night earlier, Williams acknowledged his confidence is not “as high as it’s ever been,” after essentially costing his team a third game in as many appearances.

Williams, a two-time All-Star with the Brewers who has been among the best arms in the game in his career, owns a 5.73 ERA and has allowed at least a run in his past five games.

He yielded three runs (two earned) in the 10th inning of the 5-3 loss to the Astros on Friday.

“Any time Mo’s around, I know guys — not just guys in the pen, but everyone — appreciate the wisdom he provides,” manager Aaron Boone said before hosting the Astros. “What Mariano was so good at was just that he wasn’t affected by yesterday’s performance.”

Boone has said he wants to find less-stressful situations for Williams to help reclaim his confidence.

“[Williams] needs to be a little more positive,” said Old-Timer Jorge Posada, who knew how to guide pitchers through rough times.

“You got to get him through … these key situations. Hopefully he gets his mind right.”