Newcastle midfielder Siem de Jong is expected to be ruled out for several months with a thigh injury.

De Jong only joined Newcastle from Dutch side Ajax for £6 million ($7.7 million) in August, but he is unlikely to return from injury for up to four months.

The Premier League team confirmed on Friday that the 25-year-old Netherlands international had damaged his right thigh in training.

"Siem de Jong sustained an injury to his right thigh in training earlier this week and is to be assessed further at the start of next week," a Newcastle spokesperson said.

"Initial indications are that he is likely to be out for a number of months."

The timing could hardly have been worse for Magpies manager Alan Pardew at the end of a week during which the transfer window closed without another striker being recruited, while French playmaker Hatem Ben Arfa was controversially allowed to join Hull on loan.

De Jong was seen as the man to link midfield with attack, playing behind lone frontman Emmanuel Riviere, contributing both service and goals to a team which has lost the firepower of Loic Remy and the invention of Yohan Cabaye since the turn of the year.

De Jong missed the Netherlands' friendly against Italy on Thursday because he had already been injured for the start of the English season and was instead with the rest of the Newcastle squad on Tyneside.

He is understood to have suffered the fresh injury kicking a ball in a routine training session.