PITTSBURGH >> Chicago Cubs manager Joe Maddon believes Anthony Rizzo’s slide that upended Pittsburgh Pirates catcher Elias Diaz at home plate on Monday is still perfectly legal. So does Maddon’s superstar first baseman.

Major League Baseball? Not so much.

MLB chief baseball officer Joe Torre informed both clubs on Tuesday that Rizzo should have been called for interference for swiping Diaz’s right leg while Diaz attempted to make a throw to first base to complete a potential double play in the eighth inning of Chicago’s 7-0 victory on Memorial Day.

Diaz’s throw ended up sailing into right field, allowing two runs to score. The Pirates challenged the call on the field but replay officials opted not to overturn it.

Nearly 24 hours later, MLB believes Rizzo violated Rule 6.01 (i), which states “if a runner does not engage in a bona fide slide, and initiates (or attempts to make) contact with the fielder for the purpose of breaking up a double play, he should be called for interference.”

Maddon called it the “perfect play” on Monday and didn’t back down even after what he called a respectful back-and-forth with Torre.

“There’s nothing wrong with that play,” Maddon said. “Again the umpires got it right both in New York and on the field last night. Almost like a doctor reading an MRI. You might get two different opinions on the same set of information.”

That may be part of the problem.

Asked if he believed he had a complete understanding of the rule — which was modified in 2016 — before sliding into Diaz, Rizzo responded, “I mean I don’t think anyone has clarity on the rule. It’s been in question for years.”

Rizzo said he was told that his slide was illegal but not dirty and stressed he has no plans to change his approach, noting that there’s a difference between trying to break up a double play and a collision with a catcher on a tag out at the plate, known now as the “Buster Posey Rule.” Rizzo believes if the play had happened at second base during a more traditional double play, it wouldn’t have been an issue.

“It’s just a little more sensitive when I think it’s at home plate,” Rizzo said.

Diaz lay on the ground in pain for several moments after the collision, but ultimately remained in the game. He was in the starting lineup today.

While Diaz appreciated MLB’s reversal, it also offered little solace.

“To be honest with you guys, it’s too late now,” Diaz said. “The game occurred and what happened behind the plate occurred. It’s just time to move on. I am grateful that now they’re going to become more alert and that’s going to bring me a lot more peace and a lot more catchers peace and whatever player just the peace that now MLB is going to be a lot more alert.”

Even so Diaz — who was a full step in front of home plate when Rizzo smacked into him — is going to take a more proactive approach the next time he’s in a similar situation.

“After what happened yesterday and seeing the back and forth from the decision making, I’ve came to the conclusion that no matter what, I’m just going to start protecting myself,” Diaz said.

Pirates manager Clint Hurdle worried that the original call meant it was “open season” on catchers across the league. He was ejected from Monday’s game when officials declined to overturn the call in the moment. He demurred when asked if he felt vindicated.

“Seriously, the call is made (and) life isn’t fair,” Hurdle said. “Sport isn’t fair sometimes. You play on. What’s most important from my perspective is we let the industry know this particular slide was illegal, for the sake of the catchers. That was my argument yesterday, and I’m glad we came to some conclusion and some closure.”

Rizzo offered an apology to Diaz when he came to the plate in the ninth inning on Monday, and Pittsburgh reliever Richard Rodriguez opted not to retaliate. Rizzo, who was hit a major league-leading 24 times last season, guaranteed he will be plunked at some point by the Pirates.

“If I get hit tonight, if I get hit tomorrow, if I get hit when we play them again, it happens,” he said. “Hopefully it’s in the right spot. Hopefully players pretty much know if you’re going to hit someone on purpose, you’ve got to go a little lower. It is what it is.”

Rizzo was booed boisterously when he stepped into the batter’s box today, and responded by doubling to right field.