How bad an idea is this? Let me count the ways. Old, out-of-shape, a Brave at heart, bad numbers circling the drain, National Leaguer, non-New Yorker. Some say get him if he's cheap, but I think "cheap" is also a mental mind-fck that helps you unconsciously to play "cheaply". I used to love watching Jones play with the Braves, especially when I was living in Atlanta, he was amazing, could do no wrong. Then came the last year of his contract, your try-out year, your audition-for-your-next-team year, and Andruw, really for the first time, choked, lost it, tanked bigtime. It was painful to follow: I'd always had him on a fantasy team, so I felt the decline in points and losses, if not in $$. Ouch! So... the baseball shrink says, "Don't go with over-the-hill head-cases; too much downside risk."
As for Damon... going back to players you've already broken up with can also trigger head-trips on top of physical decline. Players, teams, & fanbase know they're sloppy seconds and act accordingly. More like a booty call with your ex. Pride, Damon -- sniff the Rays.