PITTSBURGH — We interrupt your regularly scheduled coverage of The Plan and that wacky, fun-loving Cubs team to bring you a snapshot of clubhouse frustration.

Jake Arrieta sounded defensive while talking to reporters after Wednesday night’s 8-4 loss to the Pittsburgh Pirates at PNC Park, standing in front of his locker and second-guessing manager Joe Maddon. On the other side of the room, veteran catcher Miguel Montero questioned the way the Cubs are preparing for the playoffs with Cactus League scripts.

The postgame questions started with Arrieta’s first-inning issues with umpire Chris Guccione’s strike zone. When reporters mentioned Maddon’s positive spin on a seven-run outing, Arrieta dismissed those happy-talk answers about his stuff — “it just wasn’t crisp” — and then wondered why he went from throwing to Montero to rookie Willson Contreras.

“The feeling of the game, from the first pitch, just wasn’t there,” Arrieta said. “Switching catchers just felt like we were trying to do a little too much instead of win a ballgame. But I didn’t throw well, no way around it.”

Montero went with a similar passive-aggressive tone, riffing on how the Cubs will maintain their edge almost two weeks after clinching the National League Central title and nine days before their first playoff game at Wrigley Field.

“Did it feel like spring training?” Montero said. “I do believe that. And that’s not a good feeling for a pitcher, for a player, to go into a game knowing that you’re going to play just four innings or five innings or whatever it is.

“This game is still important for all the players. It’s still important for every single guy. I don’t want to go out there not caring about winning or losing. That’s not my mentality. My mentality is going out there because I want to win, regardless.

“We have to trick our mind. Because if that’s how we’re going to go the rest of the way, I guess we need to trick ourselves.”

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Unprompted, Montero brought up the Pirates scoring three runs in the ninth inning on Tuesday night before the Cubs hung on for a 6-4 victory — without using Aroldis Chapman — as Maddon tries to keep the bullpen fresh for the playoffs.

“We didn’t have our closer warming up,” Montero said. “That’s something I take personally because I’m catching and I want to win.

“It’s hard. I understand (Joe’s) point. And I understand the organization’s point. I respect it. I can only control what I can control. It is what it is.”

OK then, the Cubs are still a 101-win team and the NL’s No. 1 seed. But this became a sharp contrast to all the backslapping after the pregame announcement of Theo Epstein’s monster contract extension. And Arrieta didn’t look like a reigning Cy Young Award winner, giving up 10 hits while John Jaso — who does look like a Pirate — lined a curveball into the right-field seats for a three-run homer in the fourth inning and hit for the cycle.

“We’re moving on,” Arrieta said. “We’ll prepare for the next one. I don’t like giving up seven runs. I’m pissed about that. But moving forward, everything’s fine.”

With Jon Lester and Kyle Hendricks lined up at the front of the playoff rotation, Arrieta’s next start is almost two weeks away.

“It doesn’t matter,” Arrieta said. “I’ll throw sides. I’ll prepare. And whoever I face first round — they’re going to be in trouble.”

After burning through 103 pitches in five innings, Arrieta’s regular-season odometer is now at 197 1/3 innings, but he has zero interest in a gimmick that would get him to 200 this weekend against the Cincinnati Reds at Great American Ball Park.

“Listen, I want to pitch on a schedule,” Arrieta said. “I don’t want to throw an inning in a game. I’m not trying to do anything different. Let’s just prepare like we normally do and go out and try to win games. I’m not trying to throw a bullpen in a game.”

Look, if this isn’t trouble in paradise, then it’s obvious that the Cubs are a hyper-competitive group that knows what’s at stake in October and has some independent thinkers and strong personalities. And that Arrieta’s unreal 2015 season created impossible standards for this year that couldn’t be met with an 18-8 record and a 3.10 ERA, the type of numbers that still get pitchers $200 million contracts.

“I don’t think you know how hard this game is unless you play it,” Arrieta said. “I feel I can have another season like that. People have done it before. Why can’t I do it? I can do it again. So, yeah, I appreciate it. But at the same time, that’s what you strive for. That’s why you work hard. You go out and you try to perform that way.”