He's crap ... don't bother.
I mean in reality I really hope we can keep him for another season, by far the most naturally talented player I've seen play for Palace. Never thought anyone would ever beat Lombardo, who we had in his 30's in the late 90's, but Olise on his game is pretty much unstoppable, and with the right coaching I fully believe he could become a world class winger. At the moment he is a little all or nothing, either absolutely brilliant or doesn't seem to feature much, but the attributes are all there. I genuinely think his development would be best served with another year with us, more consistent performances, hopefully a few more goals, but obviously understand a talent like his is going to move on sooner rather than later, and Man City under Pep seems a far better place for him to develop than the basket case that is Chelsea.