Chelsea have submitted their proposal to Tosin Adarabioyo ahead of the summer transfer window.
Adarabioyo will become a free agent at the end of next month.
Newcastle United were previously favourites to sign him but now face stiff competition from the Blues.
Manchester United are the other club linked with the centre-back but failed to submit an offer for the player.
Adarabioyo made 22 appearances for Fulham this season, scoring twice.
He has spent the last four seasons with Fulham.