Town have taken former Cambridge United central defender Adam Tann on trial. The 23-year-old left the U's in the summer but is likely to cost the Blues compensation if they decide they want to sign the former England U18 international.
Boss Joe Royle said: "Adam is effectively without a club and has been training with us. He has done OK and obviously knows the game but that is it.
"Things like paying a fee are all considerations when you look at a player."
The 6ft-tall defender has also had a trial at Reading. The Fakenham-born player was a schoolboy with Norwich City.
Tann, who also plays at full-back or in midfield, is attempting to persuade the U's to waive the compensation due to them when he joins another club. Sides receive compensation when players under 24 move on even when they are out of contract.
The Blues have also been assessing another Cambridge United player, young defender Russell Short, who may join the academy after impressing in pre-season games for the reserves and U18s.
Town are also looking to Cambridge City for recruits with 14-year-old Craig Calver leaving the Conference South side's development scheme to join the Blues academy.
Royle has refuted reports earlier this week linking Arsenal striker David Bentley and Spurs defender Calum Davenport. The Town manager says he has not shown an interest in either player.