"Coaches couldn't come out and see him until July, but what he was doing in July he was doing in April and May," Team Scan coach Terrance Williams said.
"In July he caught a hot streak and when you get so many games in a short period of time a lot of people saw him in a small window," he added.
McCullough, a 6-foot-9 power forward attending Salisbury (Conn.) School, runs the floor with ease and has the ability to affect the game on the defensive end and on the glass.
"When he's at his best he should honestly average a triple double," Williams said.
"His overall game is definitely versatile," he added. "He can hit the 15-footer and on a good day step out and hit threes. He gets to the foul line a ton of times. One thing he has over a majority of the kids that are his size is his stamina and he gets up and down the court."
Despite being a 2014 prospect, McCullough is already picking up scholarship offers and interest from college programs.
To date, McCullough has offers from Florida, Providence, St. John's, Rutgers, Syracuse and Temple.
North Carolina is also among the schools recruiting McCullough. A Tar Heel assistant coach put in a call to McCullough's uncle on Tuesday.
Joining the Tar Heels in showing interest are Iowa State, Pittsburgh, Georgetown, Miami and Seton Hall.
McCullough also recently visited Rutgers and Providence and will swing by Connecticut on Thursday and then Syracuse on August 20. He's also scheduled to visit Iowa State in September.