Cambridge United manager Jez George has said he is anxious to discover the cause of midfielder Steven Connors' persistent groin problem.
The former Fleetwood man, 25, missed Saturday's 9-2 win over Biggleswade and has visited a specialist.
George told BBC Radio Cambridgeshire: "It's just a niggle and we want to get to the bottom of it soon as possible.
"He's been able to train for a day, but then he's sore, so we want to know what it is."
Defender Michael Wylde was also left out of the line-up for Saturday's game with a groin problem, but will feature against Ipswich on Tuesday.
Josh Coulson and Kieran Murtagh were both withdrawn with knocks, though George said he was not too concerned over their fitness.
"Kieran's hamstring was a little tight in the second-half against Biggleswade and he'll miss out against Ipswich, but only as a precaution really," he said.
Meanwhile, George revealed that midfielder Simon Russell is in talks with an unnamed club and could leave the Abbey before the end of the week.
Striker Daryl Clare is continuing to train with Lincoln City with a view to earning a contract.