"Never ever will I let someone speak for me," wrote Romelu Lukaku on Instagram.
"I kept my mouth shut and focused on helping the team end the season in the best way possible.
"So if someone [is] out there trying to say something about me and the club... not in my name."
The Chelsea striker has distanced himself from a controversial interview given by his agent Federico Pastorello, where he criticises Chelsea for the Belgian's struggles.
Pastorello told La Reppublica: "Given the figures of the transfer, no one could have expected such a situation. I'm not the one to discuss technical choices, but it is obvious that there was a problem.
"The numbers, however, must be weighted. He is the best scorer of the team this season, even with a lower playing time compared to his teammates."
Lukaku, who joined Chelsea for £97.5 million last summer, has scored eight goals in 25 Premier League appearances this season so far.