Every athlete experiences a “welcome to the big leagues” moment at some point in their rookie season. It may not come until halfway through the campaign, or it may come after a few games.

For Celtics rookie Robert Williams, it came even earlier than that.

Boston drafted the Texas A&M University product in the first round of the 2018 NBA Draft and he didn’t exactly make the best first impression, sleeping through his introductory conference call and later missing his flight, causing him to also miss practice with his new team.

With two mishaps happening before he even could get on the court with his teammates, it was fair to wonder if Williams would be able to mesh with everyone. But Jaylen Brown gave the 21-year-old a not-so-warm-welcome to the NBA during Williams’ first scrimmage.

“My first scrimmage with the team (Jaylen Brown) came in and caught an alley on me,” Williams told The Athletic’s Clevis Murray. “I’m talking about it was gonna be bad, too. As soon as he came down, he said, ‘Welcome to the league, rook.’ I’m like, ‘Oh aight,’ y’all coming like that now.’”

But Williams didn’t take it personal. In fact, the gesture motivated him.

“It was kind of like a boost,” he said. “It definitely turned me up a notch.”

Williams certainly has been a fan-favorite when he steps foot in TD Garden with his highlight-reel blocks, including one on New Orleans Pelicans star Anthony Davis. He’s also seen more playing time with Aron Baynes being sidelined with a fractured hand.

Thumbnail photo via Greg M. Cooper/USA TODAY Sports Images