I just Googled for details about Evans. It seems this was one of those cases where males (there were two in this case) had sex with a 19 year old female who was "deemed too drunk to consent".
Yes, the law states clearly that it is 'rape' when consent cannot be rationally given. No doubt Mr. Evans is claiming either that she did 'give consent' or at least was cooperative.

(yes...as I guessed it was one of those cases)

It is clear that very poor judgment was used by the men... but it it also common for young men in such circumstances to convince themselves that "she was aware and cooperative"...even when she was fairly well intoxicated. The girl/woman... after the fact... obviously would NOT want people to think she was cooperative in such circumstances.... and SHE may not remember clearly what she seemed to agree to. (The story also does not make clear whether the men had been drinking... and if so how much)

This sort of thing happens thousands of times every year... just not always to public figures. It is seldom clear exactly where "too drunk" begins... and obviously, the best advice to men is: "If there is any doubt, don't!" The law is one attempt to set limits and punish bad judgment. Like many "crimes of passion", the perpetrators seldom ask themselves whether they are crossing some arbitrary line.
So...Evans wants to appeal and clear his name..... no surprise. There's probably no more evidence now than there was then to decide that. The only question is: will some combination of his team & the public let him resume his career? Technically, he DID 'pay' for his bad judgment and is legally free to play, but the complex maelstrom of public opinion will probably decide whether he does.

Every day there are people convicted who should not have been and guilty ones who are never convicted or even charged. There are prosecutors who want list of convictions after their name and judges who have varying ideas of sentencing.... and when juries are involved, it becomes a game to play to the perceived attitudes of jury members.

It makes little difference to me whether he is allowed to play or not.... and I am sure glad I don't have any input on that decision!