The study is a multi-institutional, prospective trial, conducted primarily at the University of California, Davis Medical Center (UCDMC) by the Department of Surgery, Division of Trauma and Acute Care Surgery. The angioembolization arm will be multicenter while the nonoperative group will be enrolled only at UCDMC. There will be a total of 90 subjects, with 30 in each of the three arms (nonoperative, angioembolization, splenectomy).