By Chris Emma–

(CBS) — Illinois athletic director Mike Thomas spoke out Monday afternoon about 24 hours after Simon Cvijanovic, a three-year starter on the Fighting Illini offensive line, began a seven-hour, 151-tweet rant that alleged mistreatment by coach Tim Beckman and his football program.

In a Twitter rant that remains ongoing with no end in sight, Cvijanovic accused Beckman of creating a culture of mistreatment of players. He specifically alleged that at one point, he was told a meniscus tear was “no big deal.”

“There’s no doubt, it’s very serious,” Thomas said of Cvijanovic’s accusations. “Any time there are allegations made going to the safety and well-being of our student athletes, it’s something we need to pay attention to.”

Cvijanovic openly stated that the intentions of his elongated rant are for Beckman to resign, allow an increase in players speaking out about injustices in college athletics and to enable a system of checks and balances to hold athletic programs accountable.

“I stopped playing football because of my physical health,” Cvijanovic said in his first tweet. “I was asked to push myself past pain until I didn’t want to play anymore.”

As tweets continued on well past midnight of Sunday going into Monday, Cvijanovic told stories of the alleged abuse and mistreatment, including an attack on former player Kenny Knight — which Thomas said was Beckman breaking up a fight between two players — and allegations that team head trainer Toby Harkins wasn’t licensed in the state of Illinois.

Thomas confirmed that Harkins is no longer with the program and his license didn’t carry over from out of state.

However, the most significant claim is Cvijanovic suggesting a culture of abuse from Beckman and his staff. Thomas wouldn’t directly confirm a formal investigation, though he did suggest any detailed work would be handled internally.

“An internal investigation is a joke,” Cvijanovic tweeted on Monday evening.

Multiple former Fighting Illini players who spoke anonymously to CBSChicago.com — in order to avoid burning bridges — denied the allegations of a culture of abuse within the program.

“I thought it was very surprising to see this news come out, because I never saw coach Beckman in the way Simon described,” one former player said.

Another added, when asked about Cvijanovic’s comments: “Two sides to every story.”

Cvijanovic saw his football career at Illinois end with the torn labrum suffered against Ohio State on Nov. 1. Weeks later, he left the program and university, though he was reinstated to school with his eligibility exhausted.

When the football team banquet came around, Beckman decided it would be best if Cvijanovic didn’t attend, citing his exit from the program. The situation between Cvijanovic and Beckman escalated on Friday when Cvijanovic was kicked out of the coach’s office, as he alleged through Twitter.

According to Thomas, the situation went differently.

“They left the office and went to the equipment room so Simon could get his bowl gifts,” Thomas said.

On Monday morning, Cvijanovic continued his Twitter rant, saying: “I bet Coach Beckman wishes he didn’t kick me out of his office last Friday.” Later, he compared Beckman to communist North Korea leader Kim Jong-un, before deleting the tweet.

Messages to Beckman weren’t returned, and an Illinois spokesperson declined comment on behalf of Beckman, releasing a statement to the media.

“Simon Cvijanovic was a valued member of the University of Illinois football team,” Beckman said in the statement. “He chose to leave the team during the 2014 regular season and withdrew from the university before the end of the semester. Upon his return for the spring semester, we have continued to support him with medical care, an academic scholarship and academic advising. We cannot make any student accept our support.”

Ever since Thomas was made aware of the allegations Sunday evening, he and Beckman have maintained contact, with the athletic director saying the coach has handled the situation with grace. Speaking to reporters, Thomas pointed to his exit meeting with Cvijanovic, which he said went well, offering a vastly different tone from the Twitter rant. Cvijanovic tweeted that such a meeting never occurred.

Now, Thomas will begin his process of evaluating what led to this situation between a three-year starter and this football program.

“It’s disheartening that it’s happened,” Thomas said.

For now, Thomas is conducting his private research of the accusations, Beckman remains quiet and Cvijanovic is relentless in his pursuit of change.

Follow Chris on Twitter @CEmma670.