Organized sports provides numerous interesting areas of application for O.R. techniques
Game design: The point, set, game, match structure of many two person games (individual or team) can be analyzed from many points of view. Expected length of the game, variance in length of game, fairness (i.e. chances of winning the game vis a vis the probability of individual points or units of game score). Many games have undergone changes in these rules in the last 50 years, including tie breaking mechanisms.
Tournament organization: Games that are played in a league format need some principles in how teams are grouped, and what is the schedule of league matches (home and away games, stadium constraints). Knock-out formats need appropriate seeding and bracketing principles including byes in early rounds.
In game strategies: Many sports have specific strategies that allow for quantitative analysis, usually involving applied probability and odds of certain events. Examples of these are three pointers in Basketball, extra point conversion in American football, intentional walks in baseball etc.