Michael Keane, Ryan Tunnicliffe and Tom Lawrence will remain with Derby County, Ipswich Town and Carlisle United respectively, the Premier League club announced on Thursday.
Fulham, meanwhile, have chosen to recall young defender Dan Burn from Birmingham City.
The 21-year-old centre-half, who has yet to represent Fulham's first team, made 28 appearances in all competitions for Birmingham after joining the Championship club on a temporary deal in August.
Middlesbrough have confirmed that defender Justin Hoyte has joined fellow second-tier outfit Millwall on a permanent basis following a successful loan spell, while Portsmouth have taken Swansea City right-back Daniel Alfei on a one-month loan.
Marlon Harewood, Gabriel Zakuani and Dariusz Dudka are seeking new clubs, having parted company with Bristol City, Peterborough United and Birmingham.
