The 24-year-old centre-back left St James's Park in the summer after agreeing to join Portuguese champions Porto for a reported £7.14million fee.
But Mbemba, who has played just two league games since his move to Estadio do Dragao, is now being linked with a move back to the UK.
Recent reports suggest Porto are chasing Celtic youngster Olivier Ntcham and are prepared to offer Mbemba as part of the deal.
According to the Scottish Sun, "Porto are set to test Celtic’s resolve with a £14million January bid for Olivier Ntcham and are prepared to use Mbemba as a makeweight in the deal."Another man who could be on the move is Newcastle striker Elias Sorensen.
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The 20-year-old has impressed in the Checkatrade Trophy and Premier League 2 in recent months but is unlikely to break into Rafa Benitez's senior side this term.
Blackpool are one of a number of clubs who have been linked with the forward and Tangerines boss Terry McPhillips has confirmed their interest.
"We are interested in him (Sorensen), yes,"McPhillips told the Blackpool Gazette following his side's victory over Portsmouth on Saturday.
"But so are a number of other clubs so we won’t get too excited about that unless it happens."