Steve Honig, who has been the starlet's publicist for two years, reportedly resigned from the position after an alleged blowout with Michael Lohan.
The father of the Mean Girls star made headlines last week when he staged a drug intervention for his daughter, alleging it was organised with the help of her management team.
Honig released a statement over the weekend denying claims that Lindsay's manager, criminal lawyer, and entertainment lawyer helped stage the incident.
According to TMZ, Michael apparently confronted Honig about the statement, calling the publicist a "f**king liar".
Sources now claim that Honig has quit in frustration over Michael's interference, though Honig himself has commented saying: "Michael wishes he were that important."
The 25-year-old Lohan continues to deny a drug relapse despite her father's reports that she is no longer sober.