UPDATE: Dockett has torn his ACL, according to Fox Sports' Mike Garafolo.
Dockett will undergo an MRI.
Dockett, 33, has missed just two regular season games and earned three Pro Bowl appearances over 10 seasons with Arizona, which drafted him in the third round of the 2004 draft. Dockett recorded 4.5 sacks and 36 tackles last season.
The Cardinals, who went 10-6 and missed the playoffs 2013, open the season Sept. 8 against San Diego.
- Chris Johnson & Will Green