The 15-year old keeper, who currently stands at six foot three inches, was set to sign youth terms with the Dale, but with interest mounting from Chelsea's Premier League rivals Arsenal and Liverpool, the Hertfordshire Mercury is reporting that the Blues are set to move at a faster pace to secure his services.
The youngster had featured in the Rochadale Under-18 side for the duration of the season - an impressive feat for someone three years below his contemporaries - and displayed an impressive maturity, commanding his area with both his height and voice.
However, the Dale are set to miss out of cashing in on their starlet, with professional terms only allowed to be signed at the age of 17. Being two years below the legal age, the Blues can acquire Diba for next to nothing, with a nominal fee required for every year the youngster has spent with Rochale.
Although hard to gauge the potential of a 15-year old, to have been scouted by such Premier League giants can only be a positive sign for the upward trajectory of the 'keepers career.
Diba will be hoping to follow in the footsteps of Chelsea's other youth-acquired goalkeeper, Thibaut Courtois, who is set to star at the World Cup and at Stamford Bridge next season. The Belgian international, who joined the Blues as an 18-year old, as yet to feature for his parent club, but is widely regarded as one of the best 'keepers in the world.
Diba will know that he is unlikely to make an impact upon the first team for a while yet, but learning off the best in the world can only further his career.