Up until national signing day in February, Ramsey was committed to USC.
But he was one of several highly regarded recruits who changed his mind and went elsewhere.
Ramsey, who played high school football in Tennessee, said Saturday the firing of defensive backs coach Marvin Sanders influenced his decision. Sanders was fired in January 2013 after only one season on USC's staff.
"That's who I really had the connection with," Ramsey said. "I felt they really didn't give coach Sanders a chance. We were going to be his first recruiting class. We were going to be in his system."
Ramsey said he "never really clicked" with Clancy Pendergast, who had been hired as USC's defensive coordinator and coached defensive backs.
"He didn't really recruit me when he was at Cal, so I felt like he kind of inherited me, and I didn't like that," he said.
Meantime, Florida State Coach
"Coach Pruitt was with me since Day One at Alabama," Ramsey said. "He called me the day he got to Florida State and nothing changed, so I felt comfortable there. I felt comfortable with Jimbo. I knew Florida State was going to be in the top."
Ramsey said he remains in contact with USC players.
"I still talk with all my USC friends, all the time," he said. "They're still going to be like brothers to me. After seven months of being committed, you build a brotherhood."
Ramsey has observed from afar as USC went through four coaches in three months.
"Honestly, what I was thinking in my head was not that I dodged a bullet or anything like that," he said. I was thinking, 'I hope the best for those guys.'
"Unless we play them, I hope the best for those guys, because I know most of the team. I was there all the time."
Florida State freshman linebacker Matthew Thomas, also recruited by USC, underwent surgery after suffering a shoulder injury early in the season. Thomas said he has received a medical redshirt.