If they're predicting $92 million, I wouldn't be surprised if it gets even higher. The NBA tends to be conservative with these projections. For example, last April they projected $67.1 for this year and it wound up at $70 million.
$92 million means the C's would have room for two of Durant, Horford, and DeRozan without having to sweat it. At $89 million, it would have been a razor thin margin depending on cap holds for draft picks. If it gets up to $95 million, they could sign two and keep Sully, for those that want to keep him.