Ronnie Hillman ended the 2015 season as the leading rusher and touchdown-maker for the team that won the Super Bowl. He picked up his Super Bowl ring in June and his pink slip from Broncos General Manager John Elway in early September. All before his 25th birthday.

Such is the life for a typical disposable running back in today’s NFL.

“This being my fifth year, you kind of get used to the business side of the NFL and know how it works,” Hillman said. “I’m just glad they let me go so I could go do my thing somewhere else.”

But three weeks would pass before the phone rang for the young man coming off career highs for rushing yards (863), touchdowns (seven) and average yards per carry (4.2). It wasn’t until Wednesday when the Vikings needed a No. 3 running back following Adrian Peterson’s knee injury that Hillman finally found work.

“I knew the phone would ring, so I was just chillin’ and working out,” Hillman said. “Just trying to be patient.”

He’ll probably require even more patience backing up Jerick McKinnon and Matt Asiata, two guys who complement each other well. McKinnon, the starter, is the smaller, shiftier back with excellent receiving skills. Asiata is the bigger short-yardage guy and the better pass protector.

But when it comes to running backs, you never know when a guy will come out of nowhere and help a team. Of all the positions in football, running back tends to be the easiest one to strike it rich in the most unlikely of places.

“I know what you’re thinking, and historically there have been guys who have come in and have played and had a high level of success,” Vikings offensive coordinator Norv Turner said. “The right place and the right time type of situation. I think it can be done, but it’s a challenge. But I think it can be done.”

For example, in 2005, Packers General Manager Ted Thompson needed a running back. The Giants had six of them. Thompson sent a sixth-round draft pick to New York for its No. 6 back, Ryan Grant.

Grant had 956 yards, a 5.1-yard average and eight touchdowns in 2005. Then he had back-to-back 1,200-yard seasons.

Vikings quarterback Sam Bradford was asked why he thinks stories like this are more commonplace for running backs. Bradford thought about it, couldn’t figure it out and chucked it away.

“I wish I could give you more on that,” he said, “but, kind of like you said, it’s just one of those positions where every now and then guys just show up and have great years.”

Sunday, the Vikings and Panthers will play in Carolina without the running backs they drafted in the first round in 2007 (Peterson) and 2008 (Jonathan Stewart). But neither team views this as an insurmountable hurdle. Three of the NFL’s six leading rushers are backs who weren’t drafted, including C.J. Anderson, the person who made Hillman, a former third-round pick, expendable in Denver.

Peterson can be replaced satisfactorily by a former small-college option quarterback (McKinnon), a guy who entered the league as an undrafted fullback (Asiata) and a guy who was out of work five days ago (Hillman). Stewart, who has a hamstring injury, will be replaced by Carolina’s fifth-round pick in 2015 (Cameron Artis-Payne), a veteran fullback who wasn’t drafted (Mike Tolbert) and a guy who went undrafted and couldn’t even keep a roster spot in Cleveland (Fozzy Whittaker).

“With running backs, it’s just different strokes for different people,” Hillman said. “And running backs usually have chips on their shoulders. That helps. They’re going to run hard to show people they should have been drafted, or drafted higher, or not released or traded or whatever.”

He’s got a point. Stewart is the second-leading rusher in Panthers history. Whittaker is on his fourth team in five years. Yet when Stewart left last week’s game against San Francisco, Whittaker stepped in with his first 100-yard game — 16 carries for 100 — in a 19-point win.