The surprising emergence of Chris Johnson as the Arizona Cardinals‘ No. 1 running back kept David Johnson on the back burner deep into the season. But with the elder Johnson out for the season with a broken leg, the rookie from Northern Iowa has emerged as a force for the Cardinals and fantasy football owners at the most important time of the season.

After a 29-carry, 187-yard, three-touchdown performance (with four catches for 42 yards) against the Philadelphia Eagles on Sunday night, Johnson has 378 rushing yards (on 70 carries) over the last three games along with 11 receptions for 94 yards and a touchdown over that span. That production has obviously translated to fantasy points, as Johnson has 69 total fantasy points (ESPN standard scoring) over the last three weeks (40 in Week 15).

With 12 total touchdowns (seven rushing, four receiving, one kickoff return) so far this season, Johnson should clearly enter next season as the Cardinals’ No. 1 running back. Chris Johnson was playing on a one-year deal this year, and even if he is back in Arizona his role should be strictly as a backup or change of pace option next year.

Johnson suffered seemingly minor thigh and knee injuries in the last two games, but I don’t see durability as a major concern now or going forward. Legitimate workhorse running backs are rare around the league, and a couple that have served fantasy owners well (Adrian Peterson and Matt Forte) are at the age-30 threshold for decline.

Johnson currently has an every-down role in a highly productive offense. Both of those things are in line to remain the same in 2016, so Johnson is legitimately in line to be a top-five fantasy running back in all scoring formats next year.

Brad Berreman is a Senior Writer at Rant Sports.com. Follow him on Twitter.