Ellington sat out of practice on Wednesday with the foot injury, a partially torn tendon that has been bothering him all season. He has been limited at practice, but continues to play on game days.
The injury has prevented the running back from performing at full potential, Arians told Arizona Sports 98.7 FM Monday:
"It's a shame he can't practice because he's really not getting better, and some things show up on the field on Sundays -- little mistakes here and there, a couple (missed) reads. He could've had a dynamic game [against the Raiders]."
Ellington had a season-high 160 all-purpose yards Sunday. He left the game after a hit in the ribs, but returned in the second half to play through the injury.
In his rookie season last year, Ellington had 652 rushing yards with an average 5.5 yards per carry and 371 receiving yards.
The Cardinals (5-1) host the Philadelphia Eagles (5-1) at home on Sunday.
- Danielle Zhu