Not according to Ellen Zavian, who knows more about this stuff than me:
But Ellen M. Zavian, a professor of sports law at George Washington University, said in her opinion that if the players collectively decided not to work, that is a strike rather than a boycott.
“In sports, the N.B.A. players are employees, part of a union, therefore not independent contractors,” Ms. Zavian said, making their refusal to play a strike.
I stand corrected, thank you.