Lindsay Lohan won't serve a full 30 days if she is sent back to prison.

The troubled 'Machete' star - who had her latest probation order revoked and a bench warrant issued for her arrest after failing two court-ordered drugs tests last week - could be sentenced to jail at a hearing this Friday (24.09.10).

Los Angeles defence attorney Trent Copeland told The New York Daily News: "There's no question in my mind: she's getting that 30-day jail sentence. Her judge took the unusual step of allowing her to be released from in-patient rehab early. Then within days she goes out and fails a drug test. She knew what she was risking."

However, due to good behaviour and jail overcrowding experts believe the actress - who recently spent time in jail and rehab for failing to comply with the terms of her probation for a 2007 driving under influence (DUI) conviction - could be released within five days.

Lindsay's estranged father Michael Lohan believes his daughter should return to jail because of her problems, and that she is only hurting herself.

In a statement released by his attorney Lisa Bloom, he said: "The judge will probably incarcerate her again, which is sad. We have the highest incarceration rate in the world because we throw our own citizens in jail for being addicts, even when they don't hurt anyone but themselves."