Federal prosecutors want home run king Barry Bonds to spend the next few seasons in prison.

In court papers filed late Thursday, government lawyers urged a federal judge to sentence Bonds to 15 months in prison for his conviction of obstructing justice by providing evasive testimony to a federal grand jury probing the Balco steroids scandal in December 2003. Prosecutors called Bonds' denials of ever using performance enhancing drugs "patently false."

"Bonds' actions were the product of a calculated plan to obfuscate and distract the grand jury from its role in getting to the truth in the Balco inquiry," prosecutors wrote.

A federal jury in April convicted the 47-year-old Bonds of one obstruction count, deadlocking on three other perjury charges against him. Federal sentencing guidelines call for a prison term of 15 to 21 months, but no other figure convicted of lying during the Balco probe has received such a harsh sentence. Even central players in the Balco scandal, including Balco mastermind Victor Conte, received only a few months in prison for spreading steroids in sports.

Earlier this week, Bonds' lawyers argued that Bonds should get probation, citing his clean criminal record and work in the community. But prosecutors argue his conduct was egregious enough to warrant a stay behind bars longer than any figure in the longrunning Balco scandal other than Troy Ellerman, a lawyer convicted of leaking secret grand jury transcripts to the media.

U.S. District Judge Susan Illston is scheduled to sentence Bonds on Dec. 16.

Federal probation officials have recommended probation for Bonds, but with "location monitoring" for an unspecified amount of time, which would likely be a sentence of home detention. Other athletes convicted of lying in the Balco investigation have drawn similar sentences, such as former world class cyclist Tammy Thomas and track coach Trevor Graham.

Contact Howard Mintz at 408-286-0236