ALLEN PARK -- Alex Anzalone and Terrion Arnold are officially questionable to play on Sunday against the Arizona Cardinals. Both players made limited returns to practice this week and are trending toward playing in the desert, while defensive backs Ifeatu Melifonwu and Ennis Rakestraw have been ruled out.

The biggest question mark is linebacker and co-captain Alex Anzalone, who practiced Thursday and Friday but must clear concussion protocol to play Sunday.

After conducting morning walk-through, the Lions are hoping to get Terrion Arnold and Alex Anzalone actively involved in practice. This is another positive step for the pair of defenders who are integral to Detroit's defensive success.

Linebacker Alex Anzalone suffered a brain injury after taking a shot to the head from teammate Derrick Barnes in the 20-16 loss against Tampa. He’s now in concussion protocol, but already feeling better heading into the practice week for Sunday’s matchup against the Arizona Cardinals.

The Detroit Lions' Thursday injury report leading to Sunday’s game against the Arizona Cardinals resulted in three players upgraded from their Wednesday status. The full details are below. Detroit Lions Week 3 Thursday injury report Did not participate CB

The Detroit Lions returned to the practice field Thursday to continue preparing for their Week 3 matchup with the Arizona Cardinals. After several key players suffered injuries in the Week 2 loss to Tampa Bay,

Should Alex Anzalone miss Sunday's game due to a concussion, Coach Dan Campbell's confidence is high in second-year linebacker Jack Campbell.