Yaya Toure left Manchester City this summer after eight years with the club, and joined Olympiakos on 2 September
The winter transfer window is open from 1 January to 31 January in England and Scotland.
Germany's follows the same dates, Spain's opens on 2 January and Italy's runs from 3-18 January.
EFL clubs can still sign free agents as long as they left their previous club before the end of the summer window in August.
More signings: June - July - AugustManagerial ins and outs
For all the latest transfer rumours check out today's gossip column.
5 September
English Football League
Panagiotis Tachtsidis [Unattached - Nottingham Forest]
4 September
English Football League
Brad Lyons [Colerarine - Blackburn] Loan
3 September
English Football League
David Ball [Rotherham - Bradford] Loan
Elliot Ward [Unattached - Notts County] Free
Scottish Premiership
Gareth McAuley [Unattached - Rangers]
2 September
International
Yaya Toure [Unattached - Olympiakos]
1 September
English Football League
Martin Cranie [Unattached - Sheffield United]
Source: bbc.com