Josh Johnson was in the training room Tuesday when he realized his 4-year-old son Cash, a frequent visitor in the Miami Marlins clubhouse, had disappeared.

The Miami Marlins ace didn’t panic. He had a pretty good idea where Cash was — with his new best friend and “favorite player” Giancarlo Stanton.

“I look over and he’s in the weight room with Stanton on one of those physio balls, stretching with him,” Johnson said Wednesday night, moments after he and Stanton helped cap a three-game sweep of the first-place Washington Nationals and the winningest month (21-8) in team history.

“[Stanton has] always been his favorite player,” Johnson said. “He’s always come in and wanted to talk to him. But now he’s actually talking to him. He calls him Mike Stanton every time. Not Mike. Not Stanton. Mike Stanton. His whole name.”

And as far as Stanton is concerned, Cash, who leaves lollipops stashed in Stanton’s locker, is the only person allowed to still call him Mike.

The rest of the world? They’ve got to refer to him as Giancarlo, the name he has been going by since spring training, and the name the 6-5, 246-pound, 22-year-old slugger went by when he put together one of the most amazing stretches at the plate in Marlins history this May.

Sterling stats

Among the superlatives: He matched Dan Uggla’s team mark for home runs in a month (12) and tied the Texas Rangers’ Josh Hamilton for most in the majors in May; batted .343; produced 37 hits (tied for ninth in the majors); drove in 30 runs (third behind Hamilton’s 32 and Carlos Beltran’s 31); and posted an On-Base Plus Slugging of 1.201 (highest in baseball among every-day players).

“If anybody out there has better numbers [in May], congratulate them,” manager Ozzie Guillen said. “This kid is one of the biggest reasons we are where we are and we played good this month. There’s no doubt, it was because of him.”

Stanton — hitting .304 with 13 home runs and 39 RBI – put a few dents into Marlins Park and baseball’s record books along the way.

His grand slam off Jamie Moyer in a comeback win against the Colorado Rockies on May 21 shut down part of the left-field scoreboard for a half-inning and was the fastest-hit home run in the modern era — clocked at 122.4 mph. It also put him in exclusive company with Ted Williams, Eddie Mathews and Ken Griffey Jr. as the only players in major-league history with four slams before their 23rd birthday.

But that ball wasn’t even the hardest or most important one Stanton said he hit. It was his ninth-inning double off Mets closer Frank Francisco on May 11 in a 6-5 come-from-behind win that “felt the best off the bat,” he said.

Stanton, who hit 10 doubles in May, prefers good hitting days overall than big blasts and is proudest that he improved his average from .247 on April 30 to .304 heading into this weekend’s three-game series in Philadelphia.

Adjustments

Stanton gave credit to Marlins special assistant Jeff Conine for helping him go back to concentrating on hitting the ball to the opposite field during batting practice — something he wasn’t doing in April. By doing that, Stanton said it helps keep his shoulder down and his swing on top of the ball.

But catcher John Buck said Stanton deserves a lot of credit for adjusting at the plate. He said pitchers have been trying to throw inside on Stanton more often so he can’t get his arms extended and are using sliders to try to throw off his front hip.

Buck, who joked with Stanton after a rough April that all he needed was to breathe a little bit of West Coast air to get going, said the way Stanton has adjusted and continued to have success at the plate reminds him of former Blue Jays teammate and two-time home run champion Jose Bautista.

Said shortstop Jose Reyes of Stanton: “He’s only 22 years old. That’s unbelievable. Hopefully, he’ll continue to carry us all the way through.”

Cash wouldn’t have any problem with that, Johnson said.

“All he cares about is the Marlins winning and hitting,” Johnson said. “And Mike Stanton.”

Coming up

•  Friday: Marlins LHP Mark Buehrle (5-4, 3.26 ERA) at Philadelphia Phillies RHP Kyle Kendrick (1-4, 4.10).

•  Saturday: Marlins RHP Ricky Nolasco (5-3, 4.26) at Phillies LHP Cole Hamels (8-1, 2.43).

•  Scouting report: The Marlins head back to Philadelphia, where they dropped two of three in April. Buehrle was 4-0 with a 3.19 ERA in May.