It's official, the Rams' rookie minicamp has dates as the team will hold various offseason and camp exercises from late May to mid-June. OTA Offseason Workouts: May 27-28, May 30, June 2-3, June 5, June 9-10, June 12 Mandatory Minicamp: June 16-18 Rookie Minicamp: May 9-11 According to the NFL's press release.