Name your ISO "Jalen" in Battle Grids, and it links the two stories together perfectly!
In Evolution, it is briefly mentioned that Abraxas was once Jalen, the former ISO Grid Games Champion who was believed to have been derezzed.
If you play through Battle Grids as "Jalen", then you can imagine this story is the story of how Jalen became the champion, and would then later attract the attention of Clu.
Matter of fact, there's no reason to say that this wasn't likely the intention of the makers of the game anyway. It certainly makes sense to me...
One of the cool things about it, is since there is no rendition of Jalen in Evolution, it leaves his appearance up to you to decide in Battle Grids.