Atlanta United’s Andrew Carleton wasn’t selected by Tab Ramos for the U.S. U20 national team that will play in the World Cup in Poland this summer. The team, which includes nine MLS players, was announced Friday.

Asked by the media what Carleton can do to improve his chances of future call-ups, Atlanta United manager Frank de Boer said Friday that Carleton is young and has obvious quality, but needs to work on his strength and have a better understanding of what it means to be a professional.

“There are a lot of …. distractions,” de Boer said. “You fall for it or say, ‘No, I’ll stay at home.’ You see it everywhere. He’s an Atlanta United first-team player. You get a lot of attention, but you have to resist it sometimes. I think he can do better at that. He understands that.

“I think if he does that, he’s going to make a major step forward.”

An unknown distraction last season resulted in Carleton’s suspension from the team for the MLS Cup and the victory parade two days later.

Carleton, an 18-year-old Powder Springs native, has represented the U.S. on the U15 and U17 teams and played well.

His exclusion for the coming World Cup wasn’t a surprise because he isn’t receiving a lot of minutes with Atlanta United or Atlanta United 2. He has three appearances with the first team this season for a total of 64 minutes. He has five appearances with Atlanta United 2 for 415 minutes. He has one assist with Atlanta United 2.

De Boer also said that he doesn’t think Carleton has finished developing physically. De Boer compared Carleton’s growth with that of Daley Blind, an Ajax player he managed. De Boer said others doubted Blind because of his stature. De Boer said he didn’t because, as with Carleton, he could see his quality.

De Boer said he told Blind that when he was ready, go to the gym and a nutritionist. Blind started to work out, worked with the nutritionist and became stronger when he was around 20 years old. He started to play regularly with Ajax first team in 2011 when he was 21, left Ajax for Manchester United in 2014 and played well there until 2018 when returned to Ajax.

“Some are late starters in that,” de Boer said. “He (Carleton) has to deal with that. If he does that well, he has a great future here.”