Peter Kioso will miss Bolton’s home game against Morecambe after a mixed outing against Carlisle on Boxing Day.
Kioso returned from a shoulder injury at Brunton Park, scored a late equaliser in a lively 3-3 draw and then found himself sent off in the closing moments for a second yellow card.
Lloyd Isgrove impressed after being sent on as a half-time substitute against the Cumbrians and will hope to crack the XI this time.
Arthur Gnahoua (dislocated shoulder) is getting closer to full fitness but it not ready yet.
The Shrimpers will assess a handful of injuries before making the trip.
Kelvin Mellor was rated as a doubt for the win over Grimsby and did not make the matchday squad, but Adam Phillips managed 90 minutes after overcoming a knock.
A-Jay Leitch-Smith was restricted to the bench after a painkilling injection and may be set for a greater role.
John O’Sullivan is battling a new injury and Freddie Price (ankle) has yet to feature in the league this season.