Monaco striker Radamel Falcao is speaking to Chelsea about a possible transfer, Sky sources understand.
West Ham have signed goalkeeper Darren Randolph following his exit from Birmingham City.
The Ghana World Cup player will spend this season on loan in Glasgow, and Celtic have the option to make it a permanent transfer next summer.
Wakaso, who has also played for Spanish clubs Espanyol, Villarreal and Elche, has 19 international caps and featured against Germany and Portugal in Brazil this summer.
The 24-year-old will be available for Saturday's Scottish Premiership trip to Dundee.