"Football is something I will always fall back on," Peterson said. "It gets me through tough times. Just being around the guys in here, that's what I need in my life, guys supporting me. ... Things that I go through, I've said a thousand times, it helps me play this game to a different level. I'm able to kind of release a lot of my stress through this sport, so that's what I plan on doing."
Later Friday, after news of the boy's death spread, Peterson thanked his family, fans and even fans of other NFL teams for their support.
He tweeted: "The NFL is a fraternity of brothers and I am thankful for the tweets, phone calls and text messages from my fellow players."
Dozens of current and former professional athletes wished Peterson well on Twitter, expressing support, offering prayers and voicing disgust about the alleged abuse.
"Sick for my friend. Strong guy but this one will bring the strongest down," tweeted NBA star LeBron James.
The Panthers, this week's opponent, were sympathetic.
"It's absolutely terrible. Our thoughts and prayers go out to him and his family, and hopefully things work out," coach Ron Rivera said.
Vikings coach Leslie Frazier said he thought Peterson practiced as well as he could Friday considering the circumstance.
"He seems like he was into it, engaged in what he had to get done," Frazier said. "Obviously, tough. He's human. But he was into it mentally, best as he could be."
Fellow running back Toby Gerhart said: "It's hard for any man to admit that he's hurting or he needs help or anything like that. For us to be around him and tell him we've got his back, if there's anything he needs that we're there for him, I think that goes a long way."