The Seahawks had signed the 36-year-old Peterson to their practice squad earlier this week as a reinforcement for their banged-up backfield.
Peterson ranks fifth in NFL history with 14,902 career rushing yards. He spent his first 10 seasons with Minnesota and then had stints with Arizona, New Orleans, Washington and Detroit before his most recent one in Tennessee.
The Seahawks list starting running back Alex Collins and backups Rashaad Penny and Travis Homer as questionable for Sunday's game. Penny and Homer were full participants Friday while Collins was limited for a third straight day.
Coach Pete Carroll said Peterson had a "really productive" week of practice. He said one reason why the Seahawks signed Peterson was how his work ethic could rub off on others.
"It's a big part of it, just because it's a rare opportunity for our guys to see somebody like that that has that kind of background but stands for so much more than just the numbers and the stats and all of that. He's been a remarkable competitor forever and it was so obvious that it was really a boost for a bunch of guys, the young guys in particular. He's serious about playing. He's not just here for show. He's here to come here and try to help us win a game."
Information from ESPN's Brady Henderson was used in this report.