The cost of attending professional sporting events has been increasing steadily but the median household income has been relatively stagnant over the last three decades. While sport fans have increasingly spent more of their income on experiencing professional sport games, little information is available on a relationship between the costs of attending professional sporting events and sport consumers’ ability to pay and how this relationship has changed over time. Similar to housing affordability, this study proposed the concept of sport affordability, measured with a ratio between per capita income and the income needed to attend a sporting event and examined the degree of changes in the sport affordability index over time. The study results showed that the sport affordability index has become polarized among major league baseball teams. For 21 teams, the study showed that their sport affordability indexes have been deteriorating steadily over time but the trend was different for the other eight franchises. Policy and management implications related to equitable accessibility to sport and recreation events and marketing strategies are discussed.