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:
1. Hibs: Nathan Wood - IN
The highly-rated England U20 defender is expected to complete his loan move from Middlesbrough today. The 19-year-old centre-back was in the capital for his medical over the weekend and took in Hibs’ victory over Livingston on Saturday.
Photo: Stu Forster
2. Hearts: Euan Henderson - OUT
Robbie Neilson is keen to send the 21-year-old out on loan in order to get regular first team football to continue his development. It would be the second such move of his Hearts career having spent the 2018-19 season at Montrose.
Photo: Ross Parker - SNS Group
3. Hibs: Kristoffer Tønnessen - IN
The IK Start left-back has been the subject of a transfer bid from Hibs in recent days, according to reports in Norway. Whether this deal goes through though, could depend on any potential outgoings in the Hibs left-back position ...
4. Hearts: Aidan Denholm - OUT
The 17-year-old midfielder, who made his senior debut off the bench in the 3-0 win over Cove Rangers in the Premier Sports Cup in July, will be allowed to leave on loan to gain first team experience if a suitable club can be found.
Photo: Ross MacDonald - SNS Group