— Wykrhm Reddy (@wykrhm) November 3, 2016
The rules regarding substitutes were rumored a while ago. This was seen by a few as an excuse to have the famous players whose teams were unable to attend the major participate in the Major.
However Valve has skilfully worked their way around the same. Each team will only be allowed to substitute one player and only once. The substitution cannot happen unless and until the primary player agrees to the same.
Despite being as substitutes on teams playing in the Boston Major, the substitutes will still be locked on to their primary teams in the Major Roster system.
So if we were to see Dendi playing as a substitute in one of the teams attending the Boston Major he will not be released from the NaVi roster.