Although I agree that you are too deep to push, I don't think you can just call either. I think the reason you don't push is because you could go broke to BB. If you call, and BB pushes or bets big on flop, you are basically back to the same decision, but you have put an extra 500 into the pot. And you definetly don't have set odds. The only thing you can hope for by calling is that the BB folds, which he might do, but 500 is a little much to find out.