Breaking news: The March 11 Showtime card, which was to be the first boxing event at the new MGM National Harbor in Oxon Hill, Md., and feature featherweight titlist Gary Russell Jr. in a mandatory defense against interim titlist Oscar Escandon and junior middleweight titlist Jermell Charlo against mandatory challenger Charles Hatley, was postponed on Tuesday because of a back injury to Escandon. Showtime told ESPN it plans to reschedule the card.