University president Mary Sue Coleman announced Monday the NCAA has given the school a notice of inquiry.
"It marks the beginning of an investigation," NCAA spokeswoman Stacey Osburn explained.
The NCAA's enforcement staff often looks into allegations, according to Osburn, but only sends school presidents a letter of inquiry when an initial review determines a violation may have occurred based on credible information.
According to the letter sent to Coleman, the NCAA enforcement staff intends to complete the investigation by Dec. 31, 2009.
The school started looking into allegations brought against Rich Rodriguez's program in August after a report in the Detroit Free Press cited anonymous players claiming the amount of time they spent during the season and in the offseason exceeded NCAA limits.
"As I said at the onset of this review, we place the highest importance on the well-being of our student-athletes and the integrity of our program," Coleman said in a statement. "We continue to work with the NCAA to ensure that a thorough and objective investigation occurs."
Athletic director Bill Martin, who announced last week he's retiring in September, reiterated that the school contacted the Big Ten and NCAA as soon as it was made aware of the allegations.
"We remain committed to following both the letter and the intent of the NCAA rules," Martin added.
School spokesman David Ablauf said Rodriguez was not available to comment Monday evening. The day after the Detroit Free Press published its report, Rodriguez passionately defended his program that he insisted knows and follow the rules.
Rodriguez fought back tears when he talked about the perception that he and his staff do not care about their players.
"That is disheartening," Rodriguez said, then paused before looking up to finish his thought. "To say that is misleading, inaccurate and goes against everything that I have ever believed in coaching."
Players from the 2008 and 2009 team told the Free Press they at least doubled the eight hours they were supposed to spend a week in mandatory workouts during the offseason and exceeded the weekly limit of 20 hours a week during the season. They also said quality-control staff often watched seven-on-seven offseason scrimmages that are supposed to be voluntary and that only training staff are allowed to attend, according to the newspaper.
The Free Press reported the players spoke on condition of anonymity because they feared repercussions from coaches.
An NCAA survey in 2006 of 21,000 student athletes, the governing body's first attempt to measure time commitments, found football players in major programs estimated they spent 44.8 hours per week on athletic activities.