Rodriguez was sentenced for violating probation terms after her drunken driving arrest in Hawaii. She was released Thursday from a Los Angeles County jail due to overcrowding, authorities said.
The former star of ABC's "Lost" still must serve 30 days of community service and remain on probation until June 2009, a spokeswoman for the city attorney's office said.
"Our prosecutors are not happy about it, but that is the sad reality of our overcrowded jails," said spokeswoman Contessa Mankiewicz.
Calls to Rodriguez's attorney and publicist were not immediately returned Tuesday.
"Michelle's happy with the way things turned out," Rodriguez's friend, designer Anand John, told People magazine in a story posted Tuesday on its Web site. "She knows this wasn't a literal get-out-of-jail-free card. Michelle's taken responsibility for the past, and now she's ready to focus on her career."
The 27-year-old actress served five days in jail in Hawaii last month after pleading guilty to drunken driving. The Dec. 1 arrest in Honolulu violated the three-year probation term she was given in Los Angeles County in 2004 after pleading no contest to charges of hit-and-run, driving on a suspended license and drunken driving.
Rodriguez's "Lost" character, Ana Lucia, was killed off in an episode broadcast in early May. The show's producers have said the plot twist had nothing to do with her arrests.