Though Lohan, 24, is legally allowed to check out of the Betty Ford Center in California on Monday, she "may stay until the weekend to get additional treatment," the report said.
The move would be a precaution before the actress once more faces the temptations of Hollywood life, which have been the catalyst for six rehab stints since 2007.
Her latest stay was ordered by a court in October after she tested positive for cocaine while on probation for a previous offense.
The actress also spent 14 days behind bars in July for violating the terms of her 2007 DUI probation.
Ahead of her expected release, Lohan took to Twitter to express a new, spiritual outlook.
"Today is the first day of the rest of my life," she tweeted on New Year's Day. "'The future depends on what we do in the present.' -Mahatma Gandhi... One step at a time...."
But the actress faces an uphill battle to reclaim her career.
She remains under investigation for alleged misdemeanor battery on a Betty Ford worker and needs to satisfy a criminal judge that she's been in compliance with her probation terms during her three-month stint at the Ford center.
But her father, Michael Lohan, is expressing confidence as she begins her next chapter.
"She has taken the right steps and put the right people back in her life that she had at the best part of her life, to really use it as a springboard," Lohan said during an interview Monday on CBS television.
But he also sounded a familiar alarm, identifying "one imperative key element that is missing." He said that if his ex-wife Dina Lohan "can't resolve the differences she believes that we have, it's going to be a never-ending battle for Lindsay."
Lohan is due back in court Feb. 25.
NewsCore and The Associated Press contributed to this report.