It could happen, but I doubt it. Kobe has too much to lose, and even if he's guilty as hell, he's better off hoping that he can convince a jury to acquit.
I certainly don't know the facts of this case, and I'm only casually following it, but if this started out consensually, and deteriorated into rape, he's not going to get a very long sentence if he's convicted at all.
It seems as if there is plenty of room to attack the accuser as unstable and not credible based on the little I've seen. If that's so, Kobe won't plead to anything. Hell, OJ got off when the whole world KNEW he did it.