The Department of Corrections and Rehabilitation said Tuesday it will reduce its inmate population by 9,200 in time for the Dec. 27 deadline, but that's 800 short of the federal court's mandate.
The court demanded the prison population be reduced in order to improve inmate medical care.
The prison officials said even though they may miss the first deadline, their long-range plan to transfer jurisdiction over many criminals to counties is on track.
The department expects to meet a second deadline by removing 20,000 inmates by next June.
"At this point...there appears to be no need to implement additional measures or to ask that the benchmark dates be extended, when defendants' best projections show that they will achieve the June 2012 benchmark on time," attorneys for the department said in their court filing.
That conflicts with a report from the nonpartisan Legislative Analyst's Office earlier this month that urged the department to seek an extension of the deadlines. It projected that the state will miss all the deadlines and urged Gov. Jerry Brown's administration to keep more inmates in private prisons in other states.
The Associated Press contributed to this report.