Pennant has returned to training after suffering from a virus and has spoke how he is ready to get stuck in against the Londoners.
But Pulis has warned that it will be touch and go as to if he makes it.
The Stoke boss said to the Sentinel: "He has been training all right so far this week, but he's still not as sharp as he can be.
"When you've had a virus like he's had, it does take it out of you."