You are aware that the CBA you posted is the old one aren't you? Under the new CBA, a player not signed by his senior year will in effect become an UFA by August and before NHL camps open. If Oshie were to play his senior year, the Blues would have only until August to sign him. All Oshie would have to do is wait them out, become a UFA and sign with what ever team he wants to before the start of the season. The chances of the Blues letting that happen are very slim and as a result will sign Oshie before his senior year. My bet is before his Junior year, just to be on the safe side.