Pettis (ankle) participated fully in Thursday's practice, the St. Louis Post-Dispatch's Jim Thomas reports. Assuming Pettis avoids any setbacks, the full practice Thursday is a good indicator this he is on track to play Sunday against Seattle. The Seahawks defense has actually been fairly vulnerable through the air this season (19th in passing yards allowed), but Pettis' upside is capped by his position on the depth chart below Kenny Britt and Brian Quick.