I must admit that I know absolutely nothing about him apart from the fact that he was highly rated at FC Basel and he represented Switzerland U-19's during the UEFA U-19 Championship last year. This is despite the fact that he was actually born in Bosnia.
Harry says that this unknown is a "gamble" and "one for the future". I remember similar words being said about Alexander Rodic and Collins Mbesuma and look what happened to their Pompey "career".
Subotic is likely to start his career in the reserves as he has already played in last night's 0-0 draw with Chelsea reserves. If he impresses I'm sure he'll be loaned out to a lower league side before he ever makes his debut in a Pompey shirt.