(CNN) -- O.J. Murdock, who signed with the NFL's Tennessee Titans last year, killed himself Monday morning in front of the Tampa, Florida, high school where he was a track and football star, police said.
Murdock, 25, never played a game in the NFL because he had been sidelined with an injury since signing as an undrafted player a year ago.
"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," the Titans said in a statement. "He spent the last year battling back from an Achilles injury as he prepared for this year's training camp."
Titans head coach Mike Munchak, in his daily briefing with reporters Saturday, was asked why Murdock, a wide receiver, had not reported to training camp.
"He had some personal things come up," Munchak said. "He called us, and we're hoping to see him tonight."
Murdock was placed on the "did not report" list over the weekend, but he was still on the roster, team spokesman Robbie Bohren said Monday.
"Our thoughts and prayers are with his family and friends as they try to cope with this tragedy," the team statement said.
A Tampa police officer found Murdock "in his car in front of Middleton High School with an apparent self-inflicted gunshot wound" at 8:30 a.m. Monday, a police statement said.
He died two hours later at Tampa General Hospital, police said.
Murdock was ranked among the top football players in Florida and the nation in 2005 when he was a senior at Middleton High School, according to his biography on the Titans website. He was also a star sprinter on his school's track team.
His college career started at the University of South Carolina, but he transferred to Pearl River Community College after playing in just four games as a freshman. He later moved to Fort Hays State, where he played for two years.
CNN's Jillian Martin contributed to this report.