Aitor Karanka has confirmed that he and Dean Whitehead had agreed that the experienced midfielder would be better suited elsewhere next season.
Whitehead announced his Boro departure on social media this week, marking the end of the 33-year-old's two-year stay on Teesside.
Boro's season ended on Monday following the Play-Off Final and the Head Coach thanked Whitehead for his contribution while at the club.
"I was speaking with Deano (Whitehead) and I told him that it was amazing to work with him because as an experienced player he helped me a lot; especially when I came here," said Karanka.
"I told him (Whitehead) that for him and me it was going to be better to say thanks and no more because he needs to play - he deserves to play and I can't guarantee he will play here.
"He's experienced, he understood perfectly and he deserves to finish his career playing as many games as possible so I just want to say thanks to him."
Jelle Vossen's season-long loan has also come to an end and the striker has returned to Belgium following Monday's defeat at Wembley.
The Belgian scored nine goals in 42 appearances at Boro but Aitor Karanka admits he is unsure what the future holds for Vossen and whether the club will make a move for a permanent deal.
"I don't know at the moment with Jelle because I have to analyse other things before that," said Karanka.
"When I start to think about the players for the next season I can make a decision."