There's nothing to mess with; it's already added to many players. The explanation for it is somewhere in this thread. Anyways, it's loosely based on minor leaguers' arbitration eligibility, and they're given 3-5 year contracts, based on when they will a) become arbitration eligible, or become a minor league free agent. It's kind of confusing, but to answer your question, you don't have to touch anything, it's already done for you.