Currently have 13.5M in prospect $. 28k left in salary for the season. 

Bid 4M on an international (minor league deal + 7.650k salary). Bid not high enough. The engine will now not let me bid 5M or more. Says my payroll isn't large enough starting with the current season. 

What am I missing here? The prospect $ isn't offered elsewhere. And the 7.65k salary still fits under our 28k left. 

Try withdrawing your bid completely, and then resubmitting it with the higher bonus.

thanks.