The 22-year-old centre-back was being linked with an €80 million move a year ago, but Forest have managed to acquire a defender with extensive pedigree for his age at this fee. Diomande has already won a league championship at Sporting and is a senior Ivory Coast international, although his standing at his club dipped slightly last season due to injuries.
Diomande is a powerful defender who excels in the air and on the ground, and is particularly impressive carrying the ball forward. His switches of play and disguised passes add another dimension in possession, and several seasons playing in a defensive back three should ease his transition into Oliver Glasner's system.