A clause in Robinson's contract calls for him to make a $1 million bonus if he both played in at least 58 games and made the playoffs this season. Robinson's Celtics are in the postseason but he played in 56 games. As a result, the Celtics saved the $1 million they would have paid Robinson -- equivalent to a quarter of his reported annual salary -- and an additional $1 million they would have owed in luxury tax to the NBA (most of which would have been distributed to teams with payrolls below the luxury tax threshold).
They didn't really mention that games played minimum when the bonus clause was first reported this past summer. Nate'll be okay, but still...bummer for the little guy. With the caveat that I couldn't care less about the Celtics' success and would, in fact, like to see them lose in the most humiliating way possible, I'm disappointed that Nate isn't getting to spin much during the playoffs.
As a side note, if ever I'm an NBA player with such clauses in my contract, I will demand that all bonuses be delivered to me in an oversized canvas bag marked with a dollar sign.