He's okay as long as it is not tennis. He could even accept prize money for running so long as it does not exceed expenses tied to the sport:
A new set of NCAA rules, effective 8/1/2013, allow current Division I athletes in individual sports (such as Cross Country and Track & Field) to accept prize money based on performance, in an amount up to actual and necessary expenses for the calendar year (January-December).
Article 12.1.2.4.1 of the NCAA Division I Manual states:
“Exception for Prize Money Based on Performance – Sports Other Than Tennis. In sports other than tennis, an individual may accept prize money based on his or her place finish or performance in an athletics event. Such prize money may not exceed actual and necessary expenses and may be provided only by the sponsor of the event. The calculation of actual and necessary expenses shall not include the expenses or fees of anyone other than the individual.â€
Article 12.02.3 gives an understanding on how to calculate the actual and necessary expenses.
“Calculation of Actual and Necessary Expenses – Individual Sports. In individual sports, the calculation of an individual’s actual and necessary expenses shall be based on expenses incurred during each calendar year (January-December), rather than on an event-by-event basis.â€
Article 12.02.2 states permissible expenses:
“Actual and Necessary Expenses. Actual and necessary expenses are limited to:
Meals;
Lodging;
Apparel, equipment and supplies;
Coaching and instruction;
Health/medical insurance;
Transportation;
Medical treatment and physical therapy;
Facility usage;
Entry fees; and
Other reasonable expenses