Updated

By Laird Harrison

SAN FRANCISCO (Reuters) - A U.S. jury convicted Barry Bonds on Wednesday of one count of obstructing justice but deadlocked on other charges that baseball's home run king lied to a grand jury about whether he knowingly used steroids.

Bonds sat impassively as the jury was dismissed after four days of deliberations in the three-week perjury trial. His attorney, Allen Ruby, said he would file a motion to dismiss the conviction. Bonds faces up to 10 years in prison on the obstruction conviction but would likely receive far less.

U.S. Attorney Melinda Haag said the government would decide "as soon as possible" whether to seek a retrial on the three deadlocked counts. U.S. District Judge Susan Illston called a conference for May 20 to discuss the next moves in the case.

"We respect the jury's decision and their careful consideration of the evidence in this case and are gratified by the guilty verdict," Haag said in a statement.

But the trial delivered a mixed result both for the prosecution, which pursued the case for several years, and for Bonds, who was fighting for his reputation.

The charges stemmed from his testimony to a 2003 grand jury investigating the Bay Area Laboratory Co-operative, or BALCO, in a nationwide probe of the use of performance-enhancing drugs in sports.

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 had ever injected him other than medical doctors.

Many fans and sportswriters have long believed that Bonds, who holds Major League Baseball's career and single-season home run records, took performance-enhancing drugs. The steroids scandal has tarnished some of baseball's biggest stars in recent years.

Baseball Commissioner Bud Selig said the trial was a "stark illustration" of how far baseball had come, adding the sport now had a rigorous drug-testing program.

JURORS DIVIDED

Jurors after the trial told reporters they were deadlocked 11-1 in favor of conviction on a charge that Bonds lied about being injected by no one other than his doctors.

They said they were more divided on two other counts of lying about using performance-enhancing drugs and were generally wary of believing witnesses hostile to Bonds, including his former mistress and an old friend who became a business associate.

To be convicted of lying to a grand jury, prosecutors had to prove Bonds knew his testimony was false and important to their steroids investigation, court documents show.

The standard is slightly different for obstruction of justice, where the government had to show Bonds' answers were either false, evasive or misleading.

Nineteen-year-old juror Amber, who did not give her last name, told reporters she was not satisfied with his responses. "He was evasive," she said.

Bonds was one of the greatest players of his time. He was the National League's most valuable player seven times and finished his career in 2007 with 762 home runs, more than any other player in the history of Major League Baseball. Bonds, who spent much of his career with the San Francisco Giants, also set a single-season home run record with 73.

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

"(The verdict) basically confirms their belief that Bonds had taken shortcuts," said Robert Boland, a professor at New York University's Tisch Center for Sports Management.

"With Barry Bonds convicted and Roger Clemens likely coming to trial, there is some potential harm to the history of baseball. And the history of baseball is more valued than in any other sport," he said.

Clemens, who was one of baseball's greatest pitchers, has been indicted on charges of lying to the U.S. Congress when he denied using performance-enhancing drugs.

Analysts said the conviction would make it tougher for Bonds to enter baseball's Hall of Fame.

Jim Palmer, a Hall of Fame pitcher with the Baltimore Orioles, said Bonds had excelled earlier in his career before any suspicions of doping.

"It's a little bit of a tragedy," Palmer told Reuters.

(Reporting by Laird Harrison, Dan Levine and Braden Reddall; Additional reporting by Larry Fine in New York; Writing by Peter Henderson; Editing by Peter Cooney)