The forward completed a £25 million move to Liverpool on Friday.
Newcastle owner Mike Ashley (R) in the stands with Managing Director Lee Charnley
Wijnaldum completed a £25 million move to Anfield on Friday, signing a five-year deal with the Reds.
He leaves after just a year at St James Park, during which he scored 11 goals in all competitions despite their relegation to the Championship.
Georginio Wijnaldum celebrates scoring the third goal for Newcastle from the penalty spot
The fee that Liverpool have paid for the Dutchman has surprised many, especially considering that the Magpies paid PSV Eindhoven £14 million for him last summer.
And Charnley has explained that they decided to sell him as it represented the best deal for all parties involved.
"We made it very clear at the beginning of the summer that we had no need to sell for financial reasons despite relegation,” he told the club’s official website.
“After discussions with Rafa it was felt that this particular deal was one such circumstance and would be in the best interests of both parties.”
Georginio Wijnaldum celebrates after scoring the first goal for Newcastle
It now remains to be seen if Wijnaldum is the last big name to depart Newcastle United this summer.
They have lost both him and Andros Townsend in this transfer window and Moussa Sissoko has also been heavily linked with a move away.
The Magpies will likely be as resistant to selling him as they were Wijnaldum and hold out for the reported £35 million fee that has been suggested.
Georginio Wijnaldum celebrates scoring his fourth in the win over Norwich