The Redskins don't know if quarterback Donovan McNabb will be ready to play in their season opener. "I really don't know for sure," Shanahan said Sunday. "That's why it's day by day. We'll see how it goes." Washington will face Dallas in Week 1 of the regular season. McNabb hasn't practiced since spraining his left ankle in the second preseason game against Baltimore. Shanahan said the leg is too sore for McNabb to play Thursday against the Cardinals.