Chelsea legend Frank Lampard says it will not be easy for the Blues to replace striker Diego Costa.
The Spaniard will leave Stamford Bridge with Atletico Madrid a likely destination even though he would only be able to feature for them in January.
The Englishman believes a striker as equally strong as the 28-year-old is needed if the Blues are to be Premier League contenders.
"He's [Diego Costa is] a fantastic striker and we all saw that last season and since he's been at Chelsea. He would be very difficult to replace, there's no doubt about it," Lampard, Chelsea's all-time record scorer, told Sky Sports News HQ.
"I don't know where Diego Costa's mind is, whether he wants to leave or not, that's all speculation. One thing that is for sure, is that you've got a great striker in him.
"I know Romelu from playing alongside him, it was early on in his career and he probably didn't get the chances in his first spell at the club.
"He's certainly developed to a huge degree since he left the club, Romelu would certainly be a good option. The only thing Chelsea have to look at is the inflated market that is around now, it makes it very tough.
"In terms of an all-round striker, he's proven to have scored goals at Everton, but there are others. I'm sure they'll try and get a player in the same mode as Diego Costa that can give them a physical presence and 20 goals a season."
