Rangers boss Stuart McCall says he feels sorry for Gael Bigirimana, but admits he should never have been signed.
Chris Gunter will stay at Reading, after the club took up the option to extend his deal by another year.
Reports continue to suggest the Frenchman is set to leave Chinese club Shanghai Shenhua in January after a pay dispute.
England is thought to be the most likely destination for Anelka, who has spent successful spells at Arsenal, Liverpool, Manchester City and Chelsea during his career.
The 33-old striker also played for Bolton between 2006 and 2008, when he worked under Sam Allardyce and a reunion could now be possible at West Ham.
"We are looking for good players and Anelka is a good player," said assistant manager Neil McDonald in the Daily Star.
"He had a fantastic relationship with Sam."