Smart. If he gets injured in the NFL his contract could possibly plummet or Seattle (as they usually do) could go a different direction. Then he still has ties to MLB and loyalty to a team that would love to have him simply for leadership. Earn more in baseball anyway.
This isn't news to us up here and he isn't going to spring training to attempt to make the team.
The Rangers picked up his contract in the off season and all they asked was that he visits the spring training and talks to the team. I'm sure he will suit up and throw the ball around and whatnot, but he isn't going to play in games.