When choosing a recommender, you should opt for the individual who can discuss your past performance and future goals in detail. Usually, that person is your direct supervisor. However, it sounds like this might not be the case for you. Your friend can write your recommendation but make sure it is professional and does not get too personal. Your leadership, problem solving and team building skills at work are definitely more important than those same skills on the softball field.
So, the short answer is yes - your friend can write the recommendation if it is professional and addresses the topics that are relevant to MBA admissions.
Scottie Winslow | Admissions Consultant | Elite GMAT Preparation and Admissions Consulting | http://www.VeritasPrep.com