11:27 PM ET

In a letter provided to the University of California Board of regents ahead of a closed-door session Thursday to discuss UCLA's proposed move to the Big Ten conference, the Pac-12 commissioner detailed " significant concerns" he had with the move.

A source says that the regents requested the conference's perspective on UCLA's move.

"Despite all the explanations made after the fact, UCLA's decision to join the Big Ten was clearly financially motivated after the UCLA athletic department accumulated more than $100 million in debt over the past three fiscal years."

He said the increased revenue UCLA will receive would be completely offset by higher costs from added travel, competitive salaries within the Big Ten and game guarantee expenses.

UCLA spends $8.1 million a year on travel to compete in the conference. UCLA will incur a 100% increase in its team travel costs if it flies commercial in the Big Ten, a 160% increase if it charters half the time, and a 290% increase if it charter every flight.

There was no mention of how those figures were calculated or if UCLA would consider charter travel for teams other than football and basketball.

According to a source familiar with UCLA's internal estimates, the school is working with the expectation that it will spend more money on travel in the Big Ten.

UCLA would have to spend more on salaries if they moved to the Big Ten. UCLA would need to raise its athletic department salaries by about 15 million dollars to reach the average in the Big Ten, according to him.

"Any financial gains UCLA will achieve by joining the Big Ten will end up going to airline and charter companies, administrators and coaches' salaries, and other recipients," he said.

A UCLA spokesman wouldn't say anything.

UC President Michael V. Drake told the New York Times that there were no decisions. Everybody is gathering information. The situation is evolving.

Cal, which is part of the UC system, will be hurt by UCLA's planned move. It was difficult to reveal the impact without revealing confidential information, but the Pac-12 is soliciting bids with and without UCLA.

The move will have a negative impact on student-athletes' mental health and take away from the financial component. It would be difficult for family and alumni to travel to see UCLA's teams play.

Adding travel runs contrary to the UC system's climate goals and works against UCLA's commitment to "climate neutrality" by the year 2020.