This came up in the GDT last night, and it's a valid question. Apparently he's unable to play in consecutive games and even nine innings takes a pretty big toll to his body, including shaking and burning legs. A free agent at the end of the season, Baldelli will be entering the normal statistical prime, yet there's no way of knowing whether Baldelli's medical condition will leave his playing time decreasing even more as time advances.
Purely from a baseball perspective there's almost no way the Rays should bring Baldelli back as a player. Free talent can replicate his power and defense while being available to play back-to-back days. However I would imagine the Rays would be all for Baldelli returning as a consultant or advisor. Rocco retiring would probably feel like his worst decision while really being one of his best. At this point he simply needs to ensure his long-term health is as good as it can possibly be, even if that means he has to stop playing baseball.