Fourth-bottom Scunthorpe's 2-1 defeat at Bury on Tuesday night leaves 18th-placed Town six points clear of the drop zone with two matches of the season remaining, while they also boast a far superior goal difference.
Graham Turner's side will look to complete the job at the Weston Homes Community Stadium against a U's side who, sitting one place above the bottom four and five points clear themselves, still have a bit of work to do.
Striker Eaves, who registered six goals in 10 loan appearances for the Shrews, was this week recalled by parent club Bolton and so will not be available.
Defender Jermaine Grandison endured a nightmare return to action last weekend after three months on the sidelines with a hip injury - scoring an own goal in Bournemouth's 3-0 triumph before before forced off with a recurrence of the problem which will keep him out of action at Colchester.
Mark Wright (hip), Darren Jones (dislocated shoulder) and Rob Edwards (thigh) all remain unavailable, but full-back Cameron Gayle comes back into contention after a month out of action with a hamstring problem.