According to Roc Nations website, they are also a promoter:
Roc Nation Sports launched its boxing division, a full service promotional company, in August 2014.
Plus I don't think it could hurt if Jay says something about it on social media or something (I assume he has been quiet about the whole fight for the most part) especially for the most popular fighter they have in their promotion (I do think he is more popular than Ward right now). That could result in a few more ppv buys if Jay is more active like De La Hoya has been.