BORO today confirmed they will not be offering Fabio Rochemback a new contract when his current deal expires at the end of June, while Gaizka Mendieta and Dong Gook Lee have both been released.
Rochemback's initial three-year contract ends on June 30 and the club decided against an option to extend the deal by a further two years.
Boro boss Gareth Southgate said: "We both feel that the time is right for Fabio to have a fresh challenge.
"He is a talented footballer and I think he's just had his best season for us, while it was fitting that he should bow out against Manchester City on Sunday with probably his best performance in a Middlesbrough shirt."
Rochemback, who joined Boro for a undisclosed fee from Barcelona in 2005, played 91 games for Boro, scoring seven goals - including a superb free-kick in his final match for the club, Sunday's 8-1 victory over Manchester City.
The midfielder played a major role in helping Boro to reach the 2006 UEFA Cup final, a year after appearing in the final during a loan spell with Sporting Lisbon.
Former Spain midfielder Mendieta is yet to decide where his future may lay after his release. The 34-year-old joined Boro from Lazio on a free transfer in the summer of 2004 after a year-long loan spell that saw him play a key role in Boro's Carling Cup victory, the club's first ever major silverware.
He played 83 times for Boro, scoring six goals, but had not appeared for Boro's first team since a Premier League match at Everton on Boxing Day 2006.
Gareth Southgate said: "It was a difficult situation for a player of Gaizka's calibre to find himself out of the first team reckoning. It was a dent to his pride.
"I made it clear to him that he did not figure in my plans but he decided to stay and try to get back into the first team. That didn't work out but his attitude to training was always excellent and he was a good influence on some of our young reserve team players."
South Korea international Lee joined Boro on a free transfer from Pohang Steelers in January 2007. The striker scored only twice in 11 starts and 18 substitute appearances for the club and had not appeared for the first team since early February.
"We took a chance on signing Dong Gook at a time when money was tight," said Southgate. "By his own admission, he didn't play as well as he thought he could, but he was never a minute's problem.
"He has offers from clubs in Japan and possibly Germany so we wish him well, as we do with Fabio and Gaizka."
Meanwhile, Boro confirmed they have offered striker Tom Craddock and right-back Tony McMahon one-year extensions to their current deals, which run out this summer.