Asher Montain would absolutely notify his GM and/or the accounting office, and he would make sure that the money was returned OR confirm whether it was some sort of bonus that he wasn't aware of. Being a league veteran and one of the best defensive players in the league, he has been well compensated and has the accompanying sponsorship deals to supplement his contract income. Given that he didn't blow all of his money in his early years, it is not like he is yearning or needing the extra few million dollars. But, even if he could put it to good use, he knows that is not the right move. Frankly, he would also be surprised at anyone that would suggest doing otherwise. Firstly, you are working for a major corporation that has entire staffs of people crunching numbers and delivering reports about financial performance and so on. Additionally, you have to expect that the books get audited regularly. If they look at what the cap space was reported as but there is MILLIONS of dollars unaccounted for, that isn't a faux pas that ownership is going to tolerate or "waive off" and just eat that cost. Therefore, as a leader of the organization, former first round pick, and morally upstanding individual, he'd only take the money if it was intentional.