David Johnson's football story was an incredible one

David Johnson's NFL career is over, and it seemingly just started.

The former Northern Iowa running back announced his retirement on Sunday night via social media.

"I'm looking forward to my next career path in life. I don't know exactly what that will be, but I hope it will bring me the same passion, excitement, and love as football did," he wrote.

Johnson's football story, now all told, really is incredible. 

From Clinton, Iowa, Johnson was an unranked, three-sport recruit who received no Division I offers. In fact, he barely even received D-II offers. He chose between the only two schools that offered him, Northern Iowa and Illinois State, and ended up becoming a star for the UNI Panthers.

After redshirting in 2010, Johnson put up three straight 1,000-plus rushing-yard seasons while also being a major threat as a receiver. He finished his college career with 4,682 rushing yards and 49 touchdowns while also notching 1,734 receiving yards and 14 touchdown receptions.

He was a dual-threat running back star, and the Arizona Cardinals saw that star power in the 2015 NFL Draft. Johnson was selected No. 86 overall by the Cardinals and went on to have several years where he was arguably the most explosive back in the NFL.

A fantasy darling because of his ability to run and catch, he rushed for 3,128 yards and 33 touchdowns while receiving for 2,219 yards and 15 touchdowns in five seasons for Arizona. His best season, 2016, saw him put up 2,118 all-purpose yards and 20 total touchdowns en route to receiving first-team All-Pro honors.

Johnson finished his career on somewhat of a down note after the Cardinals traded him to the Houston Texans for star wide receiver DeAndre Hopkins. But without a doubt, Johnson was an explosive superstar during his prime run in the NFL.

Not bad for a former D-II athlete who nobody wanted.