Any other plan would have required taking on more long term risk, like Brantley for 3 years, or Grandal for 4 years.
Why were the Braves so risk averse medium/long term?
My theory: they couldn't take on the total debt.
MLB rules dictate a team's total debt can't exceed something like 10x their annual revenue. Since they already have a ton of stadium debt, and are planning to take on more, they simply couldn't take on the extra debt for medium/long term contracts.
And AA calls this "flexibility".