Middlesbrough winger Marvin Johnson will leave the club when his contract ends next month.
Boro have also confirmed strikers Britt Assombalonga, 28, and Ashley Fletcher, 25, will both be leaving when their deals expire this summer.
The pair cost a combined £23m when they joined in the summer of 2017 but boss Neil Warnock left them out for the final four games this season.
Goalkeeper Jordan Archer and winger Nathaniel Mendez-Laing, who both finished the season on short-term deals with the club, are not being kept on.
Archer, 28, made five appearances for the club while 29-year-old Mendez-Laing scored once in nine games.