Leigh Griffiths will go straight into the Celtic side for their Scottish Premiership clash with St Mirren at Parkhead on Sunday if his move from Wolves is completed.
Celtic are close to completing a deal to sign Leigh Griffiths - but Joe Ledley could be on his way to Crystal Palace.
Wolves striker Griffiths has agreed a three-and-a-half-year contract with the Scottish champions and is expected to be paraded before the transfer deadline.
But Ledley has a decision to make after Celtic accepted an offer for the Wales midfielder, who is out of contract in the summer and has failed to accept a new deal to stay at Parkhead.
Manager Neil Lennon this week insisted 23-year-old Scotland international Griffiths would improve his squad.
Lennon said: "He is here and the deal has been agreed so subject to a medical he will be a Celtic player hopefully before 11 o'clock tonight which I am very pleased about."
On Ledley, Lennon said: "A bid has come in from Palace and has been accepted. It is now down to the player and his representatives."
Across the city, Rangers boss Ally McCoist hopes to see out Friday without any departures. The Ibrox club - whose players rejected a 15 per cent pay cut this month - have rejected two offers from Nottingham Forest for Scotland left-back Lee Wallace.
"We will have to wait and see what happens but I'm not expecting to be busy," McCoist said.
"The club did receive a couple of offers for Lee Wallace earlier this week but they did not meet the club's valuation for the player and were rejected.
"I did notice that Forest took Danny Fox on loan until the end of the season but you would have to ask wee Billy Davies if that was the end of their interest in Lee.
"He has been one of our key players for the last couple of years, so we are very keen to keep players of his calibre.
"We have a team that is doing well in the league and it would be nice if that were to remain, but I am aware of the financial situation at the club, so we will have to wait and see what will happen."
McCoist added: "I don't think there will be the scope to bring one or two players in. I'd be very hopeful that might change in the summer."
Hibernian announced three loan additions to their side until the end of the campaign, subject to international clearance.
Terry Butcher has signed 26-year-old Notts County striker Danny Haynes, 19-year-old Sunderland winger Duncan Watmore and 21-year-old Arsenal right-back Daniel Boateng.
Dundee United agreed the loan signing of 20-year-old Newcastle central defender Curtis Good, who joins until the end of the season.
Partick Thistle brought in two midfielders on loan until the end of the campaign after Ross Forbes signed release papers to depart Firhill.
They have signed Ghana international Prince Buaben, who won the Scottish Cup during four years at Dundee United before joining Watford in 2011 and moving to Carlisle last summer.
And George Moncur - described by Thistle as a hard-tackling central midfielder - has arrived from West Ham. The 20-year-old was an England Under-18 international and has made two first-team appearances for the Hammers as well as 20 on loan at AFC Wimbledon.
Ross County completed their seventh signing of the window as 25-year-old Slovakian right-back Erik Cikos joined from Slovan Bratislava until the end of the season.
Kilmarnock have signed Sunderland winger David Moberg Karlsson on loan until the end of the season. The 19-year-old joined Sunderland for £1.5million from IFK Gothenburg last summer but has has made just one appearance for the Black Cats, in the Capital One Cup.
Killie released Portuguese wideman David Silva and teenage defender Caiomhin Bonner, while Northern Irish winger Jude Winchester has returned to his homeland to sign for Cliftonville on a three-month loan.
Meanwhile, Danny Grainger terminated his contract with St Mirren by mutual consent.
St Johnstone, meanwhile, have signed up Nottingham Forest's Mark Davies - son of City ground boss Billy Davies - on loan for the rest of the season.
The 20-year-old midfielder goes straight into the Perth squad for Saturday's League Cup semi-final with Aberdeen and is joined by Fisayo Adarabioyo, 18. The midfielder is a former Manchester City and Birmingham trainee and has joined the club until the end of the season.
However, striker Rory Fallon has been released.