Police spokeswoman Andrea Davis said officers found the 25-year-old Murdock inside his car Monday morning with what appeared to be self-inflicted gunshot wounds. The car was parked in front of Middleton High School, where Murdock attended school.
He was taken to Tampa General Hospital, where he later died.
Murdock did not report to training camp over the weekend because of what the team said at the time was a personal issue.
''We are shocked and saddened to hear of O.J. Murdock's death this morning,'' the Titans said in a statement Monday. ''In his brief time here, a number of our players, coaches and staff had grown close to O.J., and this is a difficult time for them. He spent the last year battling back from an Achilles injury as he prepared for this year's training camp. Our thoughts and prayers are with his family and friends as they try to cope with this tragedy.''
Murdock's name had not come up in the ongoing concussion debate.