Both Hearts and Hibs have already been active during the window with the Jambos adding seven in Ross Stewart, Josh Ginnelly, Beni Baningime, Cameron DevlinAlex Cochrane, Ben Woodburn and Taylor Moore, while the Hibees have brought in Jake Doyle-Hayes, Daniel Mackay and James Scott, with Chris Mueller due to arrive in January.
Both Robbie Neilson and Jack Ross are hoping to add to their squads ahead of the window slamming shut at midnight tonight, while departures are also likely, particularly on loan, and the possibility of late bids for star players cannot be ruled out.
However, loans to lower-league clubs can be done during September so there is not a desperate need to finalise them today.
Here are some of the deals that could take place at Tynecastle and Easter Road on Tuesday:
However, loans to lower-league clubs can be done during September so there is not a desperate need to finalise them today.