Defender Anthony Grant has missed the last two games after racing to 10 yellow cards this season but he is free to return against Phil Parkinson's men.
His comeback is offset by the loss of Jean-Francois Christophe, though, who picked up his fifth caution of the campaign against Norwich on Tuesday and will serve a one-match ban.
Tilson has no fresh injury concerns with Osei Sankofa (knee) still short of fitness after a two-month absence.
The Shrimpers boss could be tempted to shuffle his pack further following the 3-0 loss to Norwich.
Veteran striker Dougie Freedman could be the main beneficiary of any such changes, with the Scot hoping to be handed a starting role.