Can I sue for nonpayment of field transition bonus?

Do I have a case if I wanted to sue my employer for non payment of my promised field transition bonus? I left my field sales position to take the role of national sales trainer. I signed a contract which stated that I would be paid either the home office bonus or the field transition bonus - whichever is higher - for a period of 3 years. The field transitition bonus is significantly higher than the home office bonus. The contract is written this way to entice folks to leave the field for home office positions. The company hired a new CEO who decided that the home office bonus would not be paid for 2017. The field was paid their sales bonuses plus they were also paid an accelerator. When asked about the field transition bonus, we were told they couldn't pay it since they weren't paying the home office bonus. Even though the home office bonus was not paid, based on the terms in the contract ( "the higher of either..." ) suggests that the field transition bonus would automatically have to be paid. I would like to know if it's worth pursuing this legally. And if so, what type of attorney do I get. Do I forgo any rights if I leave the company?