Celtic manager Brendan Rodgers expects to have a stronger squad by the end of the transfer window as he predicted a "revolving door" in the final hours.
The Scottish champions are expected to wrap up deals for Augsburg midfielder Arne Engels and Sheffield United defender Auston Trusty ahead of the 11pm deadline.
They have been linked with other midfield targets including Dundee captain Luke McCowan, Switzerland Under-21 international Alvyn Sanches of Lausanne and Lyon's Mahamadou Diawara.
Rodgers said at his pre-match media conference ahead of Sunday's visit of Rangers: "We are in a really good place and we hope that by the close of the market we will have a number of signings sealed and making our squad stronger.
"That's always the goal that we entered into this window. I don't want to put any names until it's signed but that's the aim, we don't want to just regenerate the squad, we want to improve the squad, and I believe that will be the case.
"The club have been great in terms of trying to push these deals through. Quality always takes that little bit of time."
Mikey Johnston has finalised a permanent move to West Brom while Tomoki Iwata has been linked with Birmingham.
Rodgers said: "I think it's a revolving door really, there will hopefully be ones coming in and some players need to go and play. Gustaf (Lagerbielke) has already gone out and there will be a few others that need to go and play."
Scott Wright's exit from Rangers was the first confirmed move of transfer deadline day in the William Hill Premiership, joining Birmingham for an undisclosed fee reported to be around £300,000.
The former Aberdeen winger made 120 appearances for Rangers and scored 12 goals, including one in the 2022 Scottish Cup final.
Rangers are expected to sign versatile Feyenoord defender Neraysho Kasanwirjo on loan and were previously linked with Sassuolo and Albania midfielder Nedim Bajrami.
The Ibrox club are still looking to offload players, with Todd Cantwell potentially moving to Blackburn.
Motherwell secured the Premiership's first signing of the day by bringing Jack Vale back from Blackburn on a season-long loan.
St Mirren manager Stephen Robinson is hoping to get "one in at least" amid links with former Well striker Kevin van Veen, who has a year left on his Groningen contract.
"We are trying," he added. "We are always on the lookout. We are not close to anything, so it might be a long day."
Dundee United manager Jim Goodwin is hoping to confirm the arrival of a new striker on Friday evening.
"We've been needing to strengthen the top area of the pitch as Jort van der Sande and Louis Moult are the only two senior strikers in the group," he added. "I'm confident by the end of the window we'll have another one to add."
Goodwin confirmed talks over Liam Grimshaw's departure were "ongoing" but he does not want to sell teenager Brandon Forbes, who has attracted serious interest from Norwich.
"The club are not in a position where we need to sell any players," Goodwin said. "Unless it's right for us as a club, nothing will be happening on that."
The likes of St Johnstone, Aberdeen and Hibernian remain active while both Dundee and Ross County added to their squads on Thursday.
Hearts head coach Steven Naismith does not expect to be busy.
"We will wait and see how the day plays out but I don't expect to be doing loads of stuff," he said on Thursday night.
