The duration of Edin Dzeko's contract is holding up the Roma striker's move to Chelsea.

The Bosnian's representatives have been in talks this week about a return to England with Chelsea for the former Manchester City striker.

Vocegiallorossa.it says Chelsea have offered to match Dzeko's Roma contract - €4.5m-a-year to 2020. However, Dzeko is demanding an extra year to 2021.

At 31, that would mean Chelsea keeping Dzeko until he was 35, which they currently are reluctant to agree to.

Indeed, so much so, that Chelsea have let Dzeko's camp know that alternatives were contacted yesterday afternoon as negotiations continue. Arsenal striker Olivier Giroud and West Brom's Salomon Rondon were both put on notice by Chelsea intermediaries on Thursday afternoon.