Weale went down in a heap with what looked like a knee injury in the final minute of the Cobblers' 1-0 win at Sixfields on Tuesday night.
The goalkeeper, on loan from Leicester, was replaced by Freddy Hall and has returned to the Championship club to have the problem assessed by the Foxes medical staff.
With Shane Higgs already sidelined through injury, Northampton manager Aidy Boothroyd may be forced into the loan market again for a replacement if Weale's injury proves serious.
"If he is badly injured then we need to have a look at what we're going to do," Boothroyd said. "Freddy (Hall) and Neal Kitson have both done well so I've got a bit of a decision to make there.
"We need to see where we are with Chris and maybe look elsewhere if he is going to be missing for a period of time. He will go back to Leicester so they can assess him and we'll take it from there."