Swedish defender believes club have tough task replacing the Belgian striker.
West Brom defender Jonas Olsson has expressed his regret that striker Romelu Lukaku is leaving the club according to Sky Sports.
The Belgian youngster has been in great form for the club since arriving on a season long loan deal last summer.
Lukaku has established himself as an integral part of Steve Clarke’s side at the Hawthorns and is currently the club’s top scorer after hitting the back of the net on thirteen separate occasions.
No teenager has been as prolific in the Premier League since a young Michael Owen burst on the scene for Liverpool.
Lukaku looks certain to return to Chelsea this summer but is unlikely to remain at Stamford Bridge for long.
The club are keen for Lukaku to continue his development and will be looking to send the player out on loan in a similar deal that brought him to West Brom.
But a return to the Hawthorns is unlikely with Chelsea thought to be keen for Lukaku to test himself at a higher level.
The London club are hoping to find a potential suitor for Lukaku who is at least playing in the Europa League.
Olsson admitted that the club faced a tough task to replace the Belgian youngster but conceded it was not realistic to expect to hold on to the powerful forward.