Isak works at former club Real Sociedad's training ground

MADRID, Aug. 1 (Xinhua) -- Newcastle United striker Alexander Isak is working to get back to fitness at the training ground of his former club Real Sociedad.

The Swede was left out of Newcastle's Asian tour because of a thigh injury. He has been the subject of intense transfer speculation this summer, with Liverpool thought to be willing to break the Premier League's transfer record to sign him.

Isak has reportedly told Newcastle he wants to listen to other options over his future, with coach Eddie Howe commenting that Newcastle had "received no formal offer from any football club for him," before admitting Isak's future was "not in my full control."

Isak spent three successful seasons at Real Sociedad, scoring 44 goals in 132 appearances, before joining Newcastle for 63 million pounds (83 million U.S. dollars).

The deal that took him to Newcastle also included a sell-on clause with Real Sociedad due to earn 10 percent of any fee above 60.5 million pounds if Newcastle were to sell him, with a further two percent through FIFA's Solidarity Program. ■