The Town number four was forced to be withdrawn in the closing stages of the first leg tie at Portman Road with a calf problem and is now rated at 50/50 for the game.
Speaking to the Official Club Website, Town boss Joe Royle said: “John is a worry for us and didn’t train today. We will give him a run out in the morning to see how he goes. Hopefully he will come through because he is a big player for us."