Marcos Alonso
Alonso on his way to Sunderland.Reuters

Fiorentina left back Marcos Alonso will be Sunderland 's first January signing after the former Bolton defender agreed a loan deal with the Black Cats until the end of the season.

Sunderland boss Gustavo Poyet has been desperately searching for a left-back to add to his squad with Andrea Dossena his only established option in the first team. The Italian defender has failed to make an impact after moving to Sunderland from Napoli on transfer deadline-day last summer and in recent games Phil Bardsley has filled in on the left hand side of defence.

Poyet has identified former Real Madrid player Marcos Alonso as the perfect player to solve Sunderland´s defensive problems and IB Times UK understands the Spaniard has been in England today to finalise a deal that will see him join the Black Cats until the end of the season.

His agent and father, Marcos Alonso, confirmed the deal to IB Times UK. "The clubs have already agreed and Marcos (Alonso) will play at Sunderland for the next six months".

However, the deal will not be made official until the first of January, when the transfer widow opens.

Alonso already has experience in English football having enjoyed three seasons at Bolton after they paid £4m to Real Madrid to secure his services in 2010.

Last season, Alonso scored four goals in 30 appearances for the Trotters and Fiorentina signed him on a three-year deal after his contract with the Championship club expired.

The 22 year old defender has played just nine games for Fiorentina this season and he hopes to get more minutes at Sunderland.

The Black Cats have been looking for a left-back since the summer when Danny Rose returned to Tottenham after a successful season on loan at the Stadium of Light.