Arrieta is the National League’s reigning Cy Young Award winner, on the cover of “ESPN The Magazine’s Body Issue” and possibly starting the All-Star Game this summer. He is not, uh, shy or lacking confidence, but he doesn’t have all the answers, either.

The defending NL champs showed Arrieta is no longer in the zone that transformed this franchise and made the Cubs World Series favorites in 2016, optimistic projections that weren’t based on him being an ordinary or simply above-average pitcher.

“I don’t think there’s a big cause for concern,” Arrieta said after a 4-3 loss that put the Mets in position to sweep this marquee four-game series on Sunday afternoon at Citi Field. “If you’re in first or last place, every team has those spells where offensively you might struggle a little bit, things on the mound aren’t going as well as you would expect or hope. From my perspective individually, it’s one of those spells for me.

“But I’m resilient. I’ll bounce back. I’ll get to the point where I was earlier in the season – and last year – soon. It won’t continue. It’s frustrating it has for this long of a period. But we’ll make it right.”

Arrieta is now 12-3 with a 2.33 ERA, but he’s not clinging to those overall numbers, knowing he had three five-inning starts in June and couldn’t finish the sixth this time, Mets fans booing and waving goodbye as he walked off the mound with runners on the corners and one out and his team trailing 4-2.

Lefty reliever Travis Wood minimized the damage by getting Juan Lagares to ground out into a double play, but overall Arrieta felt “very odd physically,” still searching for that sense of timing, explosive stuff and finish on his pitches.

“He wasn’t comfortable, there’s no question,” manager Joe Maddon said. “If he was injured, I would be more concerned. He’s not injured. That’s the reason why I feel that he’ll be fine.”

The Mets (43-37) jumped Arrieta in the first inning when leadoff guy Brandon Nimmo – who made his big-league debut last weekend – worked a walk and Neil Walker then hammered a 3-2 pitch off a second-deck right-field advertisement for a two-run homer.

“It’s frustrating for me, just because I expect a lot more out of myself,” Arrieta said. “And to let it continue for three, four starts is not something that I like to see happen. But at the end of the day, when you put too much emphasis on certain things – and you try to make too many adjustments – that can work in reverse.

“I just need to do a better job of being aggressive early in the count and forcing the issue.”

Arrieta – who gave up eight hits and two walks against the 26 batters he faced – dismissed the idea of making a mechanical tweak or shifting his focus in-between starts while working with pitching coach Chris Bosio.

“That’s overblown,” Arrieta said. “It’s not a lot to work on, really. We’re spinning our wheels a little bit too much trying to figure out what the solution is, or is there a problem. I just need to pitch better. That’s it. Bottom line.”

Are you worried about any of this?

“No,” Arrieta said.

On a night where a 43-year-old pitcher (Bartolo Colon) limited the Cubs (51-29) to two runs across six innings – and late-inning relievers Addison Reed and Jeurys Familia got five of the last seven outs via strikeouts – the Mets made contact and put the ball in play.

The turning point came with two outs in the fourth inning, when Travis d’Arnaud lifted a flyball into shallow center field. Javier Baez raced from second base and reached out his bare right hand, but it glanced off his fingertips, falling onto the grass for a two-run hit. Whether Arrieta simply isn’t getting the breaks – or dealing with some deeper issues that aren’t a click away – the Cubs are about to find out.

“Poor performance,” Arrieta said. “The command wasn’t great. The stuff wasn’t very good. Overall, just didn’t give the effort my team needed tonight. I needed to be more of a stopper – put a stop to the bleeding.”