Mike Florio of ProFootballTalk.com reports that an MRI has confirmed that Oakland Raiders cornerback Nnamdi Asomugha has a high right ankle sprain.

Asomugha will seek a second opinion, PFT adds.

The All-Pro cornerback was injured while covering Seattle Seahawks rookie wide receiver Golden Tate on a sideline play in the 4th quarter of the Raiders' 33-3 win on Sunday. The Raiders were already playing without starting cornerback Chris Johnson, who missed yesterday's game with a concussion, prompting safety Michael Huff to play cornerback.

Johnson could return for next week's game against the Kansas City Chiefs.