"That's not fair," Peterson told NFL.com's Jeff Darlington after the NFC's first Pro Bowl practice of the week Wednesday. "Everybody's body heals differently. That's something nobody is going to understand."
Unlike Peterson, this was RG3's second ACL surgery on the right knee and third overall. That's just one of many variables that makes Griffin's timetable to return unpredictable. The surgeon who performed the surgery, orthopedist James Andrews, has said he expects Griffin to be ready by the start of next season.
That could be, Peterson says, but that timetable shouldn't be based on what the Vikings running back was able to accomplish.
"This is also a matter of genetics," Peterson said. "Look at my dad. And my mom's side, my aunts and uncles, they're all ripped. At 50 years old, they've got six packs and eight packs.
"My body just heals differently. I know it has a lot to do with rehabilitation and work ethic -- but I really credit my genetics for my recovery as much as anything else."