Bush, 30, hasn't played since making 13 appearances with the Bears last season as a short-yardage back who never lived up to the promise of the four-year deal he signed in 2012. The former Raiders starter rumbled for 977 yards with Oakland in 2011, but accounted for just 197 yards and three scores in the Windy City last autumn.
In theory, Bush gives the Cardinals a physical presence they've missed this season. Andre Ellington is a tantalizing athlete, but Arizona's inability to sustain drives on the ground cost them dearly in Sunday's loss to the Seahawks. Coming out of Week 12, only the Raiders are churning out fewer yards per outing than the Cards.