Southend United's Michael Timlin is going to be out of action for up to six weeks of action with a hamstring problem.
Oxley was brought to Southend from Hibernian with former Reading striker Cox arriving but Moussa, who ended last season with the Blues after arriving from Charlton, joined Walsall.
Brown turned down the chance to work with Allardyce, having done so with Bolton, at Sunderland. With him the England boss he could be offered a coaching role with the national side?
Southend United boss Phil Brown would be interested in the England assistant manager's job if he was offered the role.
Southend boss Phil Brown has hailed Simon Cox as a "fantastic signing" for the club after the Republic of Ireland international agreed to move to Roots Hall.
League One side Southend United sign former Reading striker Simon Cox on a two-year contract.
Leicester striker keen on Rangers move; Celtic linked with Dutch defender Jerry St. Juste and Mark Oxley seals Southend switch
League One side Southend United sign Hibernian goalkeeper Mark Oxley on a two-year contract.