Cambridge must do without midfielder Liam O'Neil when hosting Stevenage in Sky Bet League Two on Saturday.
O'Neil was concussed in a nasty clash of heads in Cambridge's goalless draw at Cheltenham on Tuesday.
Cambridge boss Sean Derry admitted O'Neil is still suffering from headaches, so is yet to be cleared for a return to action.
Jabo Ibehre remains a doubt for Cambridge, while Ade Azeez is still sidelined with knee trouble.
Stevenage boss Darren Sarll has doubts over a handful of players, including...