Bundesliga strugglers Borussia Dortmund have agreed to sign Slovenia international Kevin Kampl in January.
Cardiff have agreed to sell Norwegian midfielder Mats Daehli to Freiburg in January.
Rangers have confirmed the appointment of Craig Mather as interim chief executive in a statement to the London Stock Exchange.
The 42-year-old is a shareholder and has been the club's director of sports development since October.
He will hold the position until the Irn-Bru Third Division outfit appoint a permanent replacement for Charles Green, who resigned as chief executive with immediate effect last week.
A statement to the Stock Exchange confirmed: "Rangers announces that the Board has appointed Craig Mather, aged 42, to the role of Chief Operating Officer for the Group.
In addition, Craig will act as interim Chief Executive Officer and will be a member of the Board as the interim Chief Executive Officer.
"In the meanwhile the search for a permanent replacement for Charles Green will continue and a further announcement will be made as appropriate."
Mather invested in Rangers prior to its initial public offering in 2012 and holds 3.1 per cent of the Company's shares in issue.
His other business interests include a sports management firm and a packaging company.
He replaces Green, who became chief executive of Rangers last summer when his consortium purchased the business and assets for £5.5million after the club was consigned to liquidation following a period of administration.
Green announced on Friday he would be stepping down from the role amid claims by former owner Craig Whyte - who was at the helm when administrators were called in - that he was involved in the Green consortium's acquisition of Rangers.
The allegations prompted the Ibrox board to confirm plans to commission an independent investigation the week before Green's resignation, with law firm Pinsent Masons subsequently appointed to conduct the main investigation and Deloitte's forensic department also involved with the probe.
Green has denied any wrongdoing but felt his departure was in the best interests of Rangers after recognising the "negative publicity" was "detracting from the achievements and reputation of the club".
In another statement to the Stock Exchange on Wednesday morning, Rangers also responded to media speculation regarding Whyte's claims and "Sevco 5088", the company at the heart of the dispute.
The statement read: "In light of the recent media speculation in relation to alleged claims which are purported to have been made by Craig Whyte, Aidan Earley, Law Financial Limited or Worthington Group plc in relation to the ownership or control of Sevco 5088 Limited ("Sevco 5088"), Rangers confirms that no legal claim has been received by Charles Green, Imran Ahmad or the Group.
"As none of the allegations that have been made in the press have been substantiated by evidence of any legally enforceable rights and as details of any claim, whilst threatened, have not been received, the company regards any such press commentary and speculation to be highly spurious.
"The Group has been and continues to receive legal advice to protect the business, assets and reputation of the company and its directors from such spurious claims.
"In view of recent media speculation, the company wishes to clarify that Sevco 5088 is not an active subsidiary of the Rangers International Football Club plc.
"It is and has been a defunct non trading company over which termination proceedings began last year and which would have been struck off by the Registrar of Companies had false claims of directorships not been filed recently at Companies House.
"Sevco 5088 was listed in the company's announcement dated 22 April 2013 to comply with the AIM Rules for Companies requiring disclosure of directorships held by the directors of the company both currently and during the preceding 5 years.
"Sevco 5088 was not the acquisition vehicle which purchased the assets of Rangers Football Club."
Mather is determined to dispel any doubts fans may have about his appointment, as he revealed he wants the position on a permanent basis.
Mather acknowledges that some fans may be wary of him following another turbulent period off the field but has vowed to have a positive impact on the club.
He said: "Rangers fans have been outstanding in their support for the club during the most difficult of times and I know they don't know me and may have some doubts.
"I hope to dispel all of those if that is the case.
"I know there have been rumours about who is supposed to be connected with whom but I prefer to distance myself from all of that.
"I know what my own hard work has achieved over the years and where it has taken me and I will use of all of my experience and knowledge to help improve Rangers.
"I could not stand here and tell you I have always been a Rangers fan but I can say, with profound honesty, that I have been around football all my life and I have known of Rangers and their huge successes for many years. But then who hasn't?
"I am well aware of what this club means to so many people.
"I have been working at Rangers for the last year or so and the commitment and passion from the supporters never ceases to amaze me.
"They deserve so much better than they've been getting of late. My job will be to make sure the work is put in to make them even prouder to be Rangers fans.
"It is incumbent on everyone working for Rangers that we make sure the club is in the best possible shape for next season and to create the platform on which fans can enthusiastically support the team.
"I look forward to starting work immediately and would like to make it clear the chief executive's job is a position I would like to take on permanently."
Rangers chairman Malcolm Murray welcomed the appointment, which he says has the backing of the Ibrox board.
He said: "We are very pleased to announce the appointment of Craig Mather as Chief Operating Officer of Rangers.
"He will also be acting Chief Executive which will allow us some time to examine the credentials of candidates for this position on a permanent basis.
"Craig's appointment as Chief Operating Officer will allow the company and the Club to keep moving forward.
"Craig has invested £1million of his own money in the Club and is committed to playing an active part in delivering future success for Rangers.
"The Board has approved his appointment and look forward to him pushing us in the correct direction.
"Craig will lead the business on a day to day basis but I want to make it clear we are in a healthy position financially following the successful flotation of the company in December last year.
"I would also like to assure all of the supporters that this money is being used for the benefit of the Club and nothing or no one else."
Murray added: "The Board has also instructed the law firm Pinsent Masons to conduct the investigation into alleged links between Craig Whyte and former and current personnel at the Club.
"This process will be completed as swiftly as possible and no-one should jump to conclusions regarding the outcome.
"The fans deserve to be reassured on clarity, transparency and asset ownership and this is the main purpose of the inquiry.
"The last week or so has been turbulent for the Club but we should bear in mind that the process of rebuilding is well under way.
"Now is the time to move forward and the most important thing for all Rangers fans, myself included, is ensuring our Club can play as constructive a part in Scottish football as possible."