RealGM

The way I see it, a team could be under the cap before a season starts, have all it's players with gigantic incentive-laden contracts perform well, and then be forced to pay them to the point where their team's salaries end up over the cap.

Incentives are put into two categories Likely To Be Earned and Unlikely To Be Earned.

LTBE incentives count against the cap immediately, UTBE incentives that are met count against the cap as soon as they're earned.

So, no it can't be done.