The Brazilian is believed to have targeted a supporter who tweeted that the midfielder could be sold by Liverpool for £3 and a bag of midget gems.
In response, Lucas is said to have sent a direct message to the fellow Twitter user describing him as a "prick".
Since then, Lucas has posted: "I just want to clarify that I don't know why few people abusing me here. I always used twitter to be closer to my fans nothing else...
"If someone is trying to change it , it won't happen. I have a lot of respect for the fans who support me and the ones who don't I don't care.
"I just want to enjoy my break now. Thanks."
Lucas is on the standby list of Brazil's World Cup squad.