Most of the discussion about his comments has focused on his (probably accurate) belief that the team isn't going to contend in 2008 without getting all kinds of breaks, and his criticism of the lack of significant moves this offseason, but I think that another portion was even more significant:
"You talk to people at these things and everyone is in the best shape of their life - all that's great, but it's your job to be in the best shape of your life," Bay said. "I really don't know if that carries a ton of weight. Ultimately, if a guy reports in the worst shape of his life and goes out and performs, nobody cares."
I don't think that Bay went off on a riff about conditioning because he was up late watching World's Strongest Man reruns on ESPN2. I think he was taking an implicit shot at one or more teammates who came to play in poor shape last year, turned in a lousy season, and then tried to turn things around by buffing up the chassis this winter.
I don't have any inside sources of information here, but a quick look at the newspaper archives suggests a couple of likely candidates. Ronny Ballgame received a lot of coverage for his offseason weight loss, and Chris Duffy has been claiming that he's "in the best shape since before [he] came into professional baseball". Maybe Bay wasn't so much upset about a general lack of moves as the lack of one specific move: a deal that would put the guy in question out of a job, if not on a flight to another city.