There is fairly broad consensus that extending Prado and Heyward would be beneficial for the Braves, provided the price is right. However, while the Braves have a bevy of other potential extension candidates, none of the other cases are nearly so clear-cut.
This post will focus on the Braves' solid young 1st baseman, Freddie Freeman. The case against offering him an extension is fairly simple: there's no rush. Freeman isn't even eligible for arbitration until after the 2013 season. What's more, while a good player, Freeman doesn't project to become a superstar (as Heyward does), so locking up his FA years seems less helpful.
There is a solid case to be made for extending Freeman, however (though not until after Heyward, at least, is locked up). The idea is that Freeman is likely going to play better in the future, and thus it would be best to lock him up now while his perceived value is relatively low. This case is most persuasive if you believe something like this:
Braves Extension Analysis: Freddie Freeman
Talking Chop | Jan 8