Roos announced his decision Thursday on social media after informing the Titans.
The left tackle wrote in an Instagram post that he thought long about this decision and is grateful to start the rest of his life fully healthy. Roos wrote he feels fortunate to have played so long after starting as a tight end, then defensive end and finally an offensive tackle out of Eastern Washington.
A second-round draft pick in 2005, Roos started the first 119 games of his career and helped block for Chris Johnson's 2,006 yard rushing season in 2009.
A knee injury limited Roos to five games last season.
