The defensive end was thrown out of the game with Notre Dame after being flagged for tackling quarterback Deshone Kizer with the crown of his helmet.
It was a controversial call which was cheered loudly by the Fighting Irish fans inside University of Phoenix Stadium, as the Buckeyes have to cope without their strongest defensive player.
But it was especially hard-hitting for Bosa, just days after Buckeyes head coach Urban Meyer confirming that he would skip his senior year and declare for the NFL draft.
Today was supposed to be a crowning moment in a college career which included a national championship for Bosa – who is predicted by some to be the number one pick.
Instead, he was out of the game before the end of the first quarter and took to Twitter to apologise:
I'm sorry, I love you buckeye nation.
— Joey Bosa (@jbbigbear) January 1, 2016
Not that he needs to say sorry to most Buckeye fans – judging by the reaction they’re fully behind Bosa as his college career ends and the road to the NFL draft begins: