Plymouth manager Peter Reid admits he is being cautious over captain Carl Fletcher's return from injury.
The midfielder resumed training after missing the Pilgrim's last game against Peterborough with a thigh injury, but Reid is not making any rash decisions with other players on the injury list.
Luke Summerfield is a serious doubt with a knee injury whilst Yala Bolasie is a continued absentee with an ankle problem.
Reid told Argyle's official website: "Fletch has done a bit of running and Bolasie sees the specialist on Wednesday.
"Colchester will be too close for Summerfield but Fletch maybe, although I don't want to risk him."