ENGLAND (REUTERS) - Chelsea's record signing Alvaro Morata and Michy Batshuayi will need to make an immediate impact in the upcoming season to fill the void left by wantaway striker Diego Costa, Spanish international midfielder Cesc Fabregas has said.

Spanish international striker Morata arrived at Stamford Bridge last week for a reported fee of around £70 million (S$123 million) from Real Madrid.

He will replace Chelsea's first-choice forward Diego Costa, who has been told he will not feature in the club's plans this coming season.

With Chelsea returning to Champions League, Belgian international striker Batshuayi is also expected to shoulder Chelsea's goalscoring burden after starting only seven games in all competitions last season.

"They are two young strikers who will have to improve as quick as possible because they are our main strikers," Fabregas told reporters.

"When you are the main striker for Chelsea, you need to fight for all the competitions and if you are going to fight for all competitions, you need your strikers to score lots of goals."

"He (Morata) has a lot of potential, the same as Michy to improve. It's up to them how far they want to go."

Fabregas believes the entire squad will get more chances to prove themselves next season, with manager Antonio Conte's side hoping to challenge on domestic and European fronts.

"Last season, because of the schedule with no Champions League and we went out early in the League Cup, we were all fit for most of the season, the manager didn't have to make a lot of changes," Fabregas added.

"The manager has said himself it is a long season ahead with lots of games ...I'm sure we will have more opportunities ahead of us."

Premier League champions Chelsea will host Burnley in the opening game of their league campaign on Aug 12.