Former Chelsea scout Carlo Iacomuzzi is convinced the London giants will land Napoli star Marek Hamsik.
Inter Milan and Chelsea have been linked with the Slovakia international in the past week.
Speaking to Radio Kiss Kiss, Iacomuzzi said: "At the end of the season Chelsea will present an official offer. I have watched him many times on Chelsea's behalf.
"I know that also this year other scouts have come to Napoli to check on his progress. But watching a player like Hamsik again seems superfluous to me.
"They are no longer just looking at the player, but also at how he plays in a certain tactical scheme."
Asked to reveal how much he thinks Hamsik is worth, Iacomuzzi said: "30m could even be inferior to his real value, because Hamsik has wide margins of improvement.
"This year I am convinced that Chelsea will make Napoli an official offer for Hamsik. In my opinion he still has to improve in terms of continuity, that is playing a full 90 minutes. He takes pauses that a player of his value shouldn't be taking.
"As for the rest, he can only improve by playing in a team of champions, for example having Drogba up front, and Lampard and Ballack beside him."