CHICAGO — There are still things Greg Monroe needs to work on. His game is fitting better by the day with the Celtics.

But the hat.

It’s a problem.

Perched on the upper shelf of his locker in the visitors dressing room at the United Center late Monday night was a blue baseball cap with the intertwined “NY” facing outward.

That’s right, a Yankees hat.

Monroe laughed. He explained that he just wanted to wear something blue. When informed the Red Sox cap is also navy blue, he said the red in the logo wouldn’t work with his outfit, which, of course, featured those fashionable ripped jeans.

Monroe contended he has no baseball favorite — he was born in New Orleans, home of the Triple-A Baby Cakes — but eventually let on that the “Bronx Bombers are back.” He laughed again when told he should keep the Yankees lid tucked away when walking around Boston.

Yet, despite what the locals would term a character flaw, the bet is that Celtics followers will forgive his diamond discretion if he keeps playing the way he has in the past three games.

After struggling early as he tried to find a rhythm with his third team this season, Monroe has made 17-of-25 shots (68 percent) and averaged 14 points against Charlotte, Houston and Chicago. His best outing came against the Rockets when the Celts pounded the ball to him inside and he emerged with 18 points, including a 6-for-6 effort from the free throw line, in 19 minutes.

“It’s just getting into a rhythm, getting comfortable,” the 6-foot-11 Georgetown product said. “I’m just trying to be aggressive and make the right play. That’s it.”

Monroe began the season in Milwaukee, got traded in November to Phoenix and reached a buyout agreement with the Suns on Feb. 1. The Celts signed him as a free agent into the disabled player exception granted for Gordon Hayward’s injury.

There was some question as to how it might work out, in that Celts coach Brad Stevens likes his big people to step out, hit jumpers and space the floor. Monroe has taken just 12 3-pointers in his eight-year career and missed them all.

However, Stevens is more than capable of playing to his roster’s strengths, and Monroe wasn’t concerned.

“Nah,” he said. “If they didn’t feel like I fit, I don’t think they would have pursued me, and I’m pretty sure I wouldn’t have come. That’s stuff we talked about before I got here. And he hasn’t asked me to do anything I’m not comfortable with, and all the stuff they do already I feel like I am comfortable with. So it’s just about me getting my legs back under me and getting back into a flow.”

That flow was helped along by what happened Saturday when Monroe became a focal point against the NBA-leading Rockets. As much as the Celts already knew what he could do, it’s natural when stepping into a different locker room to want to prove one’s value to new teammates.

“Especially the situation here with these guys playing at an extremely high level,” Monroe said. “So it’s not just gaining their trust, but also making sure there’s no letdown from what they’re already doing. I just try to come in and be me. Maybe that’s why they wanted me here because of what I’ve shown I can do. I just want to add to what they already had going.”

And what they hope to keep going well into springtime. Among the reasons Monroe chose the Celtics is the opportunity for a deep postseason run. He has appeared in just one playoff series, coming off the Bucks bench to average 13.2 points and 7.3 rebounds in the six-game first-round loss to Toronto.

“I’m excited,” he said. “Right now, I’m just trying to get myself in the best shape possible and just be ready to do whatever they need me to do going down the stretch. But I’m looking forward to it.”

Monroe should have plenty of time to add to his wardrobe and put certain items on the inactive list.

“I have no loyalty to any baseball team,” he claimed again. “I just wanted a blue hat, man. We’re not in Boston right now. Hey, I get the rivalry, but I’m not from Boston, so I don’t identify with it. I could see if I had on a Lakers jersey or something. Then we’d have a problem.”

Monroe was still laughing as Andy Mannix, the assistant equipment manager and Boston diehard, walked by and shook his head.

Someone might want to start checking his shorts for Tiger Balm. Just sayin’.