I have personally asked Pres. Worthen in front of an Advisory Council (donors) meeting what the role and future is for the BYU football program. He stated three things and missionary work was not even obliquely mentioned. It is considered important to the school but not to the Church or it's missionary program.
If you have a better first hand source than Pres. Worthen formally speaking to a relatively significant group of donors, let's hear it. If not, let's get off the Church should shovel tithing or any other money into BYU football because it's important beyond the school.