SAN FRANCISCO - Barry Bonds has little chance of having his perjury case dropped.

Bonds’ lawyers were scheduled to ask U.S. District Court Judge Susan Illston on Friday to dismiss a federal indictment charging him with perjury and obstruction of justice for his grand jury testimony, in which he denied knowingly using illegal performance-enhancing drugs.

Bonds argues that prosecutors unfairly asked confusing, vague and ambiguous questions during his grand jury appearance in December 2003. The former San Francisco Giants star has pleaded not guilty. In court papers, he neither admits nor denies taking the drugs.

If the judge declines to dismiss the charges, Bonds wants prosecutors to streamline the indictment, which cites 19 different instances of Bonds’ alleged lying but only charges him with four counts of perjury and one count of obstruction.

In his papers, Bonds makes detailed attacks on every allegation and complains that each charge should cite only one instance of lying.

“It’s a really smart tactic to pick out every single question and answer,” said University of California, San Francisco law school professor Rory Little, a former federal prosecutor. “Bonds has made a very strong case that there is some duplication and some questions aren’t as well-phrased as they could be.”

But Little and other legal experts said they would be shocked if Bonds succeeds in getting the case dismissed.

Little said prosecutors may seek to file an updated indictment if the judge shows support for parts of Bonds’ arguments. Prosecutors often file new indictments that clarify charges but don’t usually alter the central accusations, according to Little.

Golden Gate University law professor Peter Keane said judges rarely toss out criminal cases, and that Bonds’ motion to dismiss the case is a routine — if doomed — defense tactic.

“Every now and then you strike oil, but I would be very surprised if Judge Illston dismissed the case,” Keane said. “It’s not going to happen.”

Keane predicted the complaints Bonds raises in his court papers would be left for a jury to decide.

Prosecutors argued in their own court filings that Bonds was advised before he began testifying that if he became confused while giving his grand jury testimony, he could consult an attorney or ask to have questions rephrased. They said he did neither.

“It’s up to the jury to decide whether he understood the questions or whether they were ambiguous,” Keane said.

Keane and others said the focus of Bonds’ case after Friday’s hearing will shift to wrangles over what evidence prosecutors have to turn over to him and what they can show the jury.

One of the most interesting pieces of evidence that could become an issue are the names and samples of major leaguers from baseball’s 2003 survey urine tests.

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The league and the players’ union agreed the players’ identities would remain confidential, but federal investigators seized the separate 1,400 samples and names in 2004 in an effort to link them.

Among those survey tests, there were 83-96 positives, Major League Baseball and the players’ union told Congress. The investigators had search warrants for only 11 players, and the union sued to have the evidence returned.

The 9th U.S. Circuit Court of Appeals ruled last month in a pair of 2-1 votes that prosecutors can keep the evidence but in a third case ruled 3-0 they couldn’t on procedural grounds. The players’ union is expected to ask for a rehearing.

“Those names will become public because the prosecution will be able to use them” to show steroids abuse was a widespread phenomenon, Keane said.

Bonds’ lead attorney, Allen Ruby, didn’t return a telephone call.