Diaby, born in 1991 in the city of Nanterre, plays as a striker and did all of his training in France at Sedan Ardennes, where he also made his professional debut.
The player signed for Lille in 2013, having been loaned several times to Belgian clubs. He ended up signing for Brugge Club, where he won two Belgian Championships and also a Super Cup.
Diaby arrives to Alvalade with the ambition to help Sporting Clube de Portugal become National Champion.