The more I look at that report, it just looks inaccurate.
It seems to suggest "The Celtics had $2.4 million. They paid Starbury $1.2 million, meaning they have $1.2 million left".
That's inaccurate. As mentioned above, the $2.4 million we had left is pro-rated downward, meaning we had $1.73 million left to offer.
Also, a pro-rated share of the NBA minimum for Starbury would have been around $900,000, rather than "less than half a million dollars".