SAN FRANCISCO (Reuters) - U.S. prosecutors on Thursday said they had not decided whether to retry baseball homerun king Barry Bonds on charges of lying to a grand jury, which was investigating steroid use in professional sports.

A Northern California jury convicted Bonds in April on a single count of obstruction of justice in a probe over the use of performance-enhancing drugs in sports, a scandal that has tarnished some of the biggest stars in baseball.

But the jury deadlocked on three other counts of lying to a grand jury, and the government could take them to trial again. Defense attorneys for the slugger have asked that the one conviction be thrown out, or that the charge be retried.

Bonds appeared at a hearing on Thursday in a dark suit and blue tie, looking at ease.

U.S. District Judge Susan Illston told lawyers that the government should not have to decide whether to retry the three unresolved charges until the fate of the conviction was clear.

Assistant U.S. Attorney Matthew Parrella told Illston that the government had not decided whether to retry Bonds.

A hearing on the conviction motions is expected on August 26.

All the charges stemmed from Bonds' testimony to a 2003 grand jury investigating the Bay Area Laboratory Co-operative, or BALCO.

Testifying to the grand jury, Bonds admitted getting flaxseed oil, vitamins, protein shakes and creams from his trainer, but he said he had no knowledge of human growth hormones or steroids. He said no one ever injected him other than medical doctors.

Bonds was the National League's most valuable player seven times and finished his career in 2007 with 762 home runs, most in the history of Major League Baseball. Bonds, who spent much of his career with the San Francisco Giants, also set the single-season home run record with 73 in 2001.

He was indicted three months after breaking Hank Aaron's career homer record in 2007.

The case in U.S. District Court, Northern District of California is United States of America v. Barry Lamar Bonds, 07-cr-0732.

(Reporting by Peter Henderson)