Judge Elden Fox issued -- but held until Friday morning -- a bench warrant for Lohan's arrest. At the hearing, Fox will decide whether Lohan violated her probation.
The judge's decision to revoke probation came after Lohan admitted last week that she failed a court-ordered drug test. The LA County Probation Department delivered its findings Monday to Fox.
In a series of Twitter messages late Friday, Lohan confirmed what had been previously reported by other media outlets.
"Regrettably, I did in fact fail my most recent drug test and if I am asked, I am prepared to appear before judge Fox next week as a result.
"Substance abuse is a disease, which unfortunately doesn't go away over night. I am working hard to overcome it and am taking positive steps forward every day. I am testing every single day and doing what I must do to prevent any mishaps in the future.
"This was certainly a setback for me but I am taking responsibility for my actions and I'm prepared to face the consequences. I am so thankful for the support of my fans, loved ones and immediate family, who understand that I am trying hard, but also that I am a work in progress, just as anyone else. I am keeping my faith, and I am hopeful....Thank you all!!!"
Lohan was released from rehab in August. The actress served 14 days of a 90-day jail sentence over the summer for violating the terms of her probation in a 2007 DUI case.
She was similarly released early from a 90-day rehab sentence after serving 23 days at UCLA Medical Center and must undergo twice weekly random drug tests.
Fox's decision Friday could affect plans to begin filming Lohan's next movie, "Inferno," a Linda Lovelace biopic. Producers have denied they're upset with Lohan.
Filming was set to begin Nov. 15.
"Did this throw us for a U-turn? Sure," director Matthew Wilder said of last week's development. "[But] This is not something to be pissed about. If someone fails a drug test but says I am trying hard and struggling, it's hard for me to be angry."
Not all news was bad for Lohan on Monday. A lawyer for the actress told TMZ that she’d reached a confidential settlement with E*Trade over a $100 million “milkaholic” lawsuit alleging the financial firm violated her rights by using a baby in a commercial that traded on her name.
"The family is pleased that the case has been settled," Dina Lohan told TMZ.