Foster was carted off the field during Sunday's preseason game against the Dallas Cowboys.
The 24-year-old was headed into his third season in the NFL and second with the Cardinals, hoping to earn backup running back duties behind starter David Johnson.
Foster finished last season with just six carries for 19 yards but he made a larger impact in the passing game, totaling 17 catches for 133 yards.
Of course, most of the players ahead of him on the depth chart from last year are gone, including Adrian Peterson, Kerwynn Williams and Chris Johnson.
The latest injury ruins the former undrafted free agent's best chance to earn regular playing time at this level.
Meanwhile, the Cardinals will now be even more reliant on David Johnson after he missed all but one game last season due to a wrist injury.
Rookie fourth-round pick Chase Edmonds and second-year player T.J. Logan will likely become the team's top options off the bench at running back this season.