Getty Joe Mazzulla, Boston Celtics The Boston Celtics have been heavily linked with a move for Giannis Antetokounmpo this summer. However, there’s no guarantee Brad Stevens will strike a deal with the Milwaukee Bucks . As such, Boston should be lining up a list of secondary trade targets to ensure Joe Mazzulla’s roster improves ahead of the new season. According to Bleacher Report’s Grant Hughes, Onyeka Okongwu of the Atlanta Hawks would be an ideal ‘Plan B.’ “Onyeka Okongwu isn’t a better