I doubt that very much. You still need an agent to be in place, and to negotiate your bonus when drafted (whether it's for millions or thousands) and to deal with your qualifying offers after the first year (even if most of them are boilerplate), and to file a grievance for your when your team messes with your service time before you've even played a game.
Now, it's possible an agent may choose to take nothing initially - in fact, many agents are probably lending their clients money against future commissions when they are in the minors. But they still get their cut. (And not just of salary, too. Most agencies deal with sponsorships and endorsements as well). It all goes on the ledger.
Anyway, yes, everything in julio's post is true, which is exactly why there are agents out there who may be more inclined to complain about the Phillies, a team that had a huge payroll and signed numerous external high-$ free agents, but not the Braves.
