Mike Zimmer went through his entire podium session at the NFL Scouting Combine without a single question directly about Adrian Peterson.

It was a stark contrast to the previous year in Indianapolis when rumors had Peterson unlikely to return to the Vikings for the 2015 season.

Peterson did so emphatically, proving that there's football life for some running backs after 30. Peterson led the NFL with 327 carries for 1,485 yards and tied for the most rushing touchdowns (11) in the league, claiming his third rushing title and being named to his seventh Pro Bowl in nine seasons.

Vikings General Manager Rick Spielman's podium session included two questions about Peterson, specifically if he has to think about life after Peterson or if that was too far down the road to consider.

"You're always thinking about it. At running back, you're one injury away. We'll eventually get down there," Spielman said. "I think Adrian is still a very productive running back in this league. He won the rushing title again this year. It's amazing, the stamina [he has] and the physical specimen that he still is, but at some point, everybody has to retire. I don't know when that point is. Adrian may defy the odds and play until he's 50. I don't know."

After the joke, Spielman then pivoted into excitement about younger players. He and Zimmer have been pleased with the way that Matt Asiata, who is scheduled to be a free agent, has stepped in to fill a variety of roles the past two seasons. They're also high on 2014 third-round pick Jerick McKinnon, who averaged 5.2 yards per carry last season (271 yards on 52 carries) that included a 68-yard touchdown run against the Giants. McKinnon added 21 catches for 173 yards.

"When he has an opportunity to get the ball in his hands, he shows he can be a very explosive playmaker as well," Spielman said. "When you're building a roster, regardless if you have an Adrian Peterson or not, you've got to anticipate the potential disaster of a player being gone because of an injury and how you're still going to be an effective football team even if he's not there."

A total of 29 running backs were invited to the combine this year. They have made the rounds with media members and for formal and informal interviews with personnel from NFL teams. The prospects will cap their time in Indianapolis with on-field workouts Friday.

Spielman also was asked about workload for Peterson, who added 30 catches for 222 yards in 2015, but the GM deferred commenting on usage to Zimmer.

The 2007 first-round pick will turn 31 in March and enter the 2016 season with 2,381 career carries for 11,675 yards, a rush total that ranks 17th all-time in NFL history.

Zimmer told beat writers that Peterson can still carry the load, but the Vikings feel confident in sharing duties.

"I think he can still handle the same role he's had," Zimmer said. "I think we have to do a better job of continuing to try to get him some more space to run so he's not running into 100 guys all the time, but I do feel good about McKinnon's role to take some plays off him because he's good, and also Asiata if we get him back."

Toward the end of the season, the Vikings worked in more reps for McKinnon, even occasionally finding ways for he and Peterson to be on the field simultaneously. Indications are that the Vikings liked that look and are excited about expanding it this season.

Part of the changes will be to Vikings assistants. Minnesota hired Tony Sparano as offensive line coach, Pat Shurmur as tight ends coach and slid Kevin Stefanski from tight ends to running backs this season.

McKinnon told Vikings.com last week at Polaris-Vikings Winterfest that he's excited to work with Stefanski.

"Coach Stefanski knows us well, and we know him well," McKinnon said. "I think it will be good. I'm really excited to work with Coach Stefanski. That will be another way of me learning more about route running as well, especially with how I came on at the end of last year."