A team from League One or League Two is assured of a place in the Petrofac Training Cup final following a semi-final draw that pairs Rangers or Livingston with St Mirren.
It means that only one of the three remaining Championship clubs can make it through to face either Queen's Park or League One's Peterhead.
Rangers' had their quarter-final tie postponed because of international commitments.
They face Livingston on 20 October.
The winners will have a home tie against St Mirren, while the Spiders host Peterhead at Hampden Park.
Petrofac Training Cup semi-final draw
Rangers or Livingston v St Mirren
Queen's Park v Peterhead