Very early in free agency, the Titans lost linebacker Avery Williamson to the New York Jets. Williamson has spent his entire career to this point in a Tennessee, almost entirely as a starter at inside linebacker.
Even if you are in the camp that believes Williamson was overrated and not incredibly valuable, you must acknowledge the fact that his departure will leave a hole in the middle of the Titans defense.
Aside from Wesley Woodyard, the Titans do not have a bonafide starter at inside linebacker on their roster. Jayon Brown is probably too small for an every-down role, and free agent signee Will Compton is probably best suited with a situational role as well.
So, with free agency pretty much over, the Titans will need to turn to the 2018 NFL Draft to find their next starter at inside linebacker. When they do, they will likely target one of these players.