Colin McCarthy is a talented player that has been a sparkplug for the Titans defense, no one is debating that. When he is in the game the Titans look much more versatile and become much more effective against the short pass and the run. However the third year LB hasn't been on the field very much due to injury, and I am concerned.
The rangy MLB has been hobbled by another leg injury (his third in three years), and he is becoming less and less dependable. The question for the Titans now isn't whether he will miss time every year, it is how much time will he miss and does that warrant looking at replacements?
The way I see it there are three options:
Option one: The Titans could stay the course with McCarthy and try to minimize his reps by pulling him out in sub packages.
For example, McCarthy can play first and second down, and then allow a cover LB/DB to come into the game and give the Titans more freedom to blitz for different areas. This mentality means that McCarthy would play much less during the course of a season, but it would also limit the Titans third down run defense. If the team faces run-heavy opposition like the Redskins or 49ers then they could be in for a long day.
Option two: The front office agrees that they will allow McCarthy to continue his cheap rookie contract in Tennessee, but during that time they will look for a capable replacement. This gives the Titans a long period of time to try to find someone that fits the identity of their defense.
Over the next two years, the front office can evaluate draft talent and possibly sneak out a day two or day three draft gem that can come in and be effective. This will prevent the franchise from being pigeon-holed into a bad deal, meaning either drafting someone too high or overpaying for free agents.
Option three: If the Titans are fed up with worrying about whether or not he can play, they can immediately move him to second team MLB, pushing Moise Fokou into the lineup. With a healthy stop-gap the Titans can accurately evaluate how he handles the responsibility. If he can't keep up then they can make a move to trade, sign, or draft a MLB at over-market cost in the offseason. This option isn't ideal, but it would be a decisive course of action that the front office may decide to take.
Either way, the Titans coaches and fans would love to see a healthy McCarthy, and a healthy #52 is the best case-scenario.