This season, Zormelo worked with All-Stars like Paul George of the Indiana Pacers, John Wall of the Washington Wizards and Rajon Rondo of the Boston Celtics. At least three of his clients are still in the playoffs. When they require hands-on involvement, he heads to the airport.

Image A page from Zormelo’s notebook. He works for players, not their teams. Credit... Max Reed for The New York Times

Zormelo declined to say what he charges his clients, but said he was “definitely not rich by any means” and was still building his business.

“This is competitive for me,” Zormelo said. “If my players lose, I take it personally. Especially if they’re doing what I tell them to do.”

Last month, Zormelo was at his computer watching film of Wall’s effort against the Chicago Bulls in Game 1 of their first-round series. The Wizards won, but Wall shot 4 of 14 from the field. Zormelo highlighted an area of concern: Wall was leaving his feet too often before making passes. Zormelo wanted Wall to be more decisive.

“No more getting caught in the air,” Zormelo wrote in a text message to Wall. “They saw that, and they will stay at home when you drive and look for steals in Game 2.”

Zormelo reinforced the point by sending Wall an email with sequences of game footage. Wall responded via text: “I appreciate it a lot. I agree. I think I need to be more aggressive attacking the basket.”

Over the next four games, Wall averaged 19.5 points and 7 assists as the Wizards advanced to the Eastern Conference semifinals.