From my knowlede he is a good prospect. He is a great checker who has a lot of speed and has been given credit for his attitude and work ethic. Some people credit the success of the Korpedo-Nokelainen-Tukkonen line last year to his play.
He will take a few years at least to develop so dont plan on seeing him next season. He probably doesn't have top line ability. Think a tough and fast second line LW who could be the motor for his line.
He's out til mid November... but should be back for WJC. Before he went down his coach gave him a lot of praise for his progression as a rookie.. he even got some 1st line duty with his Finnish team which is an accomplishment in itself.
I'll cite Padawan for this info since most of it came from him over in Finland if you want to check out the Immonen and Korpikoski thread.