Middlesbrough have released Willo Flood and Maxi Haas, while Andrew Davies is to return to Stoke.
Midfielder Flood was signed from Celtic by former Boro boss Gordon Strachan in January 2010 but has struggled to make an impression on Teesside.
Ex-Bayern Munich defender Haas has also failed to produce his best at the Riverside Stadium and will not be offered a new deal as a result.
Davies, meanwhile, will be sent back to parent club Stoke, having spent the final three months of the season with Boro.
Tony Mowbray, who inherited the managerial reins from Strachan in October, is now looking to piece together a squad he feels will be capable of pushing for promotion in 2011/12.
He told the club's official website: "I'm aware that Willo started very well when he came here and I can see exactly what assets he brings to the team.
"But I'm looking to put my own stamp on the team and I need to create space in the squad to enable me to bring in my own players.
"We did have an option to give Maxi a further year on his contract, but I have decided to let him move on.
"Andrew did very well for us at Millwall, but unfortunately has been injured for much of the time since then, which has limited the number of games he has played for us."