Doing it unconditionally is dumb. I guarantee you 30 mins and a starting role, even if you suck, are lazy or become a locker room cancer.
Alternatively, he could say as the roster sits right now, based on your talent and continued hard work you have a good shot at starting and 25-30 mins a game. I plan to use you in the game plan as a point guard that plays the off guard at times. This is all conditional on you beating out other players competing for the same role. I think you would be a great fit here. We would love to have you. Are you up for the challenge?