McGreal's U21s face table topping City.
They are without Jamie Harney and Kevin Lokko, who are both injured, whilst a number of players with experience of first team football have travelled.
The U's lost their last game to Charlton, and will be looking to bounce back in their latest outing.
The match, to be played at the Swans' training ground, will see the U's take on the table topping Welsh side, who are currently enjoying an extended unbeaten run.
Colchester United's U21s are back in action on Monday night, as they make the long trip to face Swansea City.O'Donoghue, Lapslie, Lawrence, Curtis, Szmodics, Bonne, Smith, Sembie-Ferris, Robinson, Harrison, Issa, James, Stevens