"As long as Bortles is back there, if the ballgame is in his hands, he's going to choke," Casey told 104.5 The Zone in Nashville on Tuesday.
Casey's most recent comments come two days after he challenged the Jaguars' credentials as true contenders following the Titans' 15-10 win to complete a regular-season sweep of the AFC South champions.
"We didn't want their offense to score at all," Casey said. "And it looks like that's what happened. It looks like that's what happened. Sorry. At the beginning of the week, I was talking about that.
"King of the South? King of the South? Sounds great, but gotta be able to beat us. Jacksonville didn't play great today. Appreciate the turnovers. Helped us out a lot."
Titans safety Kevin Byard intercepted Bortles twice on Sunday.
Jacksonville won the AFC South by one game over Tennessee, which plays the Kansas City Chiefs in the wild-card round of the playoffs Saturday.
Jacksonville hosts the Buffalo Bills on Sunday.
The Titans and Jaguars could only meet in the playoffs if both teams advance to the AFC Championship. However, these past few days have provided enough ammunition to ignite the rivalry when they play next season.