The Indianapolis Colts placed running back Marlon Mack on the Injured Reserve list with a torn Achilles tendon on Wednesday.
Mack, 24, was carted to the locker room during the first half of the Colts' season-opening 27-20 loss to the Jaguars in Jacksonville. The season-ending injury was later confirmed by an MRI.
Mack was injured after catching a pass over the middle and then attempting to turn upfield. He was able to get to his feet but limped significantly while motioning to the sideline before being tended to on the field by the team's medical staff.
He had four carries for 26 yards and three receptions for 30 yards for the Colts, who will rely on rookie Jonathan Taylor and third-year back Nyheim Hines in his absence.
The team added wide receiver Daurice Fountain from the practice squad to the 53-man roster in Mack's place. Running back Darius Jackson was signed to the practice squad.
Mark recorded career highs in both carries (247) and rushing yards (1,091) to go along with eight touchdowns in 14 games (12 starts) last season. He also had 14 catches for 82 yards.
A fourth-round pick in the 2017 NFL Draft out of South Florida, Mack has rushed for 2,383 yards and 20 touchdowns in 41 career games. He has 55 receptions for 440 yards and two scores.
Mack has a $2.1 million base salary for this season, the final year of his four-year rookie deal.
--Field Level Media