The 22-year-old has played three times for The Toffees this season and also has had loan spells at Doncaster Rovers and Crystal Palace.
Turner has also been a part of the full Scottish squad but has found his Goodison Park opportunities limited because of the form of Tim Howard and ex-England stopper Richard Wright who is currently the back up.
Mark Crossley will still be at Hillsborough though until the end of the season - the on-loan Fulham star's form has dropped in recent weeks and that has forced Brian Laws to bring in the highly-rated Turner.
Graham Coughlan is pushing for a starting spot tomorrow against The Shrimpers and could be brought in to sure up the defence.
Deon Burton is set to start after his best goal-scoring run of the season and should be partnered up front by Steve MacLean or Leon Clarke.
Jermaine Johnson is set to make his home debut as Wade Small is still carrying a knock although Frankie Simek has been troubled with a virus and could miss out.