Dutch international Siem de Jong ended his injury-plagued three-year spell at Newcastle United on Monday by re-signing for Dutch giants Ajax, the English club announced.

The 28-year-old attacking midfielder -- who suffered a collapsed lung and a ruptured thigh muscle among other injuries after moving to England for £6million (6.4m euros, $7.7m) in 2014 -- joins French striker Emmanuel Riviere in being moved on by Magpies manager Rafael Benitez.

De Jong made just 26 appearances for Newcastle and spent last season on loan at PSV Eindhoven.

Spaniard Benitez hopes that by off-loading players he will be allowed to bring in new faces before the transfer window closes on Thursday.

"Siem de Jong has completed a permanent transfer to Dutch side Ajax," read the Newcastle statement.

"The 28-year-old returns to the Amsterdam Arena, where he made over 200 appearances before signing for the Magpies in the summer of 2014."

Benitez, who saw his side beat West Ham United 3-0 on Saturday to record their first win since returning to the Premier League, has also told, among others, Tim Krul, Achraf Lazaar, Grant Hanley and Jack Colback that they can leave.

Benitez has been engaged in a tussle with Newcastle's controversial owner Mike Ashley over transfers during the close season, expressing his frustration at missing out on several targets.