Chelsea midfielder Nathaniel Chalobah has returned to his parent club following the end of his loan spell with Nottingham Forest.
Meanwhile, the Reds have also allowed Kuwaiti goalkeeper Khaled Al Rashidi to leave the City Ground.
Chalobah, who shone in the Championship last season during a loan spell with Watford, failed to scale those heights with Forest as he made a total of 12 appearances after arriving from Stamford Bridge in September.
The England Under-21 international scored two goals during his stay in the East Midlands.
Al Rashidi, who signed for the Reds last January, provided cover for Karl Darlow towards the end of the 2012-13 campaign but a string of injuries this season limited his opportunities.