Advertisement: Service time is the amount of time that a player has been on an active MLB roster or the injured list. A player becomes a free agent at the end of the season where they reach six years of service time. One year of service time, the maximum amount a player can gain in one season, is 172 days. A single baseball season lasts 187 days. Simply, a player must be on a Major League roster or injured list in all but 15 days of a typical season to be able to accumulate one year of service time. This is where the manipulation can happen.