The Yankees already have changed hitting coaches, and now they are bringing in a familiar face and longtime big-game performer to help with their pitching mindset for the playoff push.

Core Four stalwart Andy Pettitte is returning to work for the Yankees as an adviser to Aaron Boone, the Yankee skipper confirmed after Sunday’s 8-5 win over the Royals.

Bringing back the five-time World Series champion has been discussed in past seasons, Boone said, but Pettitte appears to be willing to spend as much time around the team as his schedule will allow for the remainder of the season.

“I never wanted Andy to leave, so I was trying to make this happen for a long time,” Boone said. “Andy and I talk frequently during the season. COVID kind of threw things out of whack a little bit, but we’re getting him back to where we can get him back into the fold.

“He’s been coaching back at home [in Texas] with his boys. It took longer than I would have liked, but I’m excited to have him back in the mix. And as I tell him, the more he can be here, the better.”

Pettitte retired following the 2013 season after pitching for 15 seasons in three stints with the Yanks, interrupted by three years with the Astros (2003-05) and a brief retirement in 2011.

Pettitte, whose No. 46 is retired in Monument Park, was part of the large contingent who watched rehabbing reliever Jonathan Loaisiga pitch to injured captain Aaron Judge (toe) during a simulated game Sunday morning.

“He’s just such a great sounding board, a resource, smart. Not only for the pitchers, but the position players as well,” Boone said. “For being Andy Pettitte, there’s the humility when he walks in that room, but what a genuine impact he’s able to have with guys. Just excited to have him in the mix moving forward.”

The addition continues to signal an added organizational emphasis on experience to Boone’s staff, perhaps at the expense of analytical expertise.

After a brutal first half in which their bats underperformed, the Yankees fired hitting coach Dillon Lawson, who did not play in the majors, and replaced him with Sean Casey, a career .302 hitter over 12 MLB seasons.

It appears that Pettitte — whose 19 career postseason wins are the most in MLB history — will work alongside pitching coach Matt Blake, although Boone indicated that he is unsure how frequently the 51-year-old pinstriped legend will be around the team.

“It’s kind of his schedule where, as I tell him, as much as he can,” Boone said. “Obviously he’s got obligations back at home. So we’ll see him at times where he’ll pop in on the road. We’ll see him here. I’m saving a seat for him on the plane whenever he wants to jump in.”

Asked what he expects Pettitte’s role to be, Boone replied, “Just impact the players, like he does. He’s got a good relationship with Matt and Hark [bullpen coach Mike Harkey] and the pitching guys. He communicates with different pitchers throughout the season via phone. He does it with position players, too. So I just want him breathing into our guys.”

–Additional reporting with Mark W. Sanchez