Marcos Alonso: Gus Poyet keen on permanent deal for 2013-14 loanee

Sunderland have made a formal offer to Fiorentina for defender Marcos Alonso, Sky sources understand.

Alonso, predominately a left-back, spent a successful spell on loan at the Stadium of Light last season, making a total of 20 appearances and helping them avoid relegation from the Premier League.

The 23-year-old has also been linked with Premier League rivals West Ham and Swansea, and Sky sources understand he has told Fiorentina he wants to leave.

He only managed three appearances in Serie A after joining Fiorentina in May 2013 from Bolton but did play six more times in the Europa League.

He started his career in his home town with Real Madrid, playing regularly for reserve side Castilla, but he did make one senior appearance off the bench at the end of the 2009-10 season before leaving for Bolton.