SAN FRANCISCO — Federal prosecutors are urging an appellate court to let them present critical evidence they say proves Barry Bonds knowingly used steroids.

A trial court judge excluded urine samples and other evidence from the upcoming trial of the San Francisco Giants slugger, who is accused of making false statements to a grand jury and obstructing justice. The judge says that evidence connected to Bonds' personal trainer Greg Anderson could only be used if Anderson testifies. Anderson says he'd rather go to jail than testify.

Bonds has pleaded not guilty to charges he lied to a grand jury in 2003 when he said he never knowingly used performance-enhancing drugs.