Former running back Steven Jackson said Thursday on Twitter that the NFL contacted him for a random drug test after he signed a one-day contract to retire as a member of the Rams:

The news shocked a couple of Jackson's former Rams teammates in James Laurinaitis and Chris Long:

Jackson, who is the Rams' all-time leading rusher with 10,138 yards, signed the one-day deal on Monday and took part in a special ceremony at the team's training camp. 

The 36-year-old spent the first nine seasons of his 12-year career with the Rams. During that time, Jackson was named a Pro Bowler on three occasions.

Jackson went on to spend two seasons with the Atlanta Falcons, and he appeared in two games for the New England Patriots in 2015 but has not played since.

Overall, Jackson rushed for 11,438 yards and 69 touchdowns, while catching 461 passes for 3,683 yards and nine scores during his career.