Updated

Cardinals All-Pro cornerback Patrick Peterson was diagnosed with a concussion following a helmet-to-helmet collision with Eagles wide receiver Jeremy Maclin on Sunday.

Maclin caught a short pass from Nick Foles early in the second quarter and was sandwiched immediately by Peterson and Cardinals safety Deone Bucannon, whose helmet fell off upon impact.

Bucannon quickly recovered, but Peterson and Maclin remained on the ground motionless for several moments.

Peterson stayed on the field longer than Maclin, and both walked gingerly off the field and into the locker room.

Maclin was back on the field later in the half, but Peterson failed the concussion protocol and did not return.