Formerly of Stade de Reims in France, 20-year-old Sylla joins Boro as a free agent on a one-year contract, while 17-year-old Sinior has signed on a two-year deal from Legia Warsaw.

Sylla, an attacking midfielder from France, has previous with Boro, having played against our Under-18s for Stade de Reims in the UEFA Youth League back in 2015.

Meanwhile, Polish youngster Sinior will bolster defensive options at our Academy at centre-back.

Jakub Sinior