Joe Mauer called Twins equipment manager Rod McCormick on Saturday morning with an urgent and unexpected request: I’m going to catch again, but I don’t have a helmet anymore.

He was in luck. Mostly.

“I said, ‘I know exactly where your old white helmet is. It’s in my garage. My kids play with it,’ ” McCormick said. “It’s a little beat up. It’s bounced on our driveway a few times. But it still fits.”

And with that dinged-up detail taken care of, Mauer gave the go-ahead for one of most memorable farewells — perhaps — in Twins history. Mauer’s symbolic return, for one emotional pitch, to the position that made him one of the franchise’s greatest players was months in the making but came together in just a day.

“It kind of stemmed from Joe and I sitting on the bench one day earlier this season, having a conversation about stuff he would still like to do, and catching came up,” said Twins bench coach Derek Shelton, who believed it was a wish that the Twins, playing out their schedule far from playoff contention, could grant. He discussed the idea with longtime bullpen catcher Nate Dammann, “because I knew he and Joe are pretty tight,” Shelton said. “But we didn’t really know how Joe would react.”

They found out Friday. Shelton pulled Mauer into McCormick’s office and described the scenario. “It’s funny, Nate happened to walk in two minutes later. And Nate’s perspective was really good,” Shelton said. “They’re both from [the Twin Cities]. Joe’s such a humble guy, but Nate pointed out how much it would mean to other people, too, in addition to Joe.”

His reaction? “I think he was in shock,” Dammann said. “He didn’t say much. He kind of stared at us.”

Turns out, though, that Shelton wasn’t the only one who had longed to see Mauer wear the equipment again. Mauer’s father, Jake, had made the suggestion to his daughter-in-law earlier in September. “But I said, ‘You probably shouldn’t say anything to Joe,’ ” Jake Mauer said.

She did, though, but Mauer didn’t follow through — until Shelton and Dammann made their case. The thought of delighting his father on such a big day swayed him.

“I wanted it to be a surprise for my dad,” Mauer said. “So just a few people knew.”

One was Matt Belisle, his teammate for the past two seasons, whom Mauer asked to throw the pitch.

“When he approached me about this a few days ago, I was just really blown away with humility, to have an honor bestowed on me in that regard. So of course I told him, ‘If you want to do this, I’m in your corner like cast iron, I’ll do whatever you want,’ ” Belisle said. “I just wanted to do my best to make it about him and have it as special as it can be.”

Twins manager Paul Molitor contacted his counterpart, Rick Renteria, to make sure the White Sox were OK with the idea, and Mauer made sure his wife, Maddie, had no objections.

“As long as the White Sox player did not swing,” Maddie Mauer said, “I was on board with it.”

Mauer knew right where to find his old chest protector and shin guards. He kept them in a bag in his basement, planning to someday turn it into a shadowbox exhibit in his home. “I haven’t opened that bag since 2013,” he said, the last time he was a catcher.

And once McCormick dug Mauer’s mask and helmet out of a bucket in the garage, everything was set for Mauer’s big surprise.

“I had no idea it was coming,” Jake Mauer said. “But when there was a delay, I put two and two together and thought, ‘He’s putting on the catching gear, I know he is.’ ”

Mauer strode up the steps and into the loudest ovation of a day full of them. “The moment that that idea became was way cooler that I could have imagined,” Shelton said. “In terms of sentimental moments, how could you top that?”

Just one problem: The helmet isn’t the Twins’ standard anymore. Technically, Mauer broke the MLB uniform rules.

“He’s probably OK, though,” McCormick said. “Usually, you get a warning for a first offense.”