Major leaguers Jason and Jeremy Giambi were expected to testify Tuesday as Barry Bonds' perjury trial resumed.
It's expected that the brothers will be the first of several athletes called to testify. Both have admitted to using performance-enhancing drugs they obtained from Bonds' personal trainer, Greg Anderson.
Other athletes who are on the government's witness list include several former teammates of Bonds: Armando Rios, Benito Santiago, Bobby Estalella and Marvin Benard.
All the players except Jason Giambi, who is with the Colorado Rockies, have retired.
Bonds, MLB's record-holder for home runs in a career (762) and a season (73), is accused of lying to a federal grand jury for testifying in 2003 that he never knowingly used performance-enhancing drugs.
Prosecutors hope to use the players' testimony to bolster their position that Bonds knowingly used steroids obtained from Anderson.
As the trial resumed, the testimony remained intimately personal for Bonds, though not as personal as Monday's testimony from Kimberly Bell, Bonds' former mistress.
Prosecutors called two witnesses to the stand to discuss the urine samples Bonds provided during the 2003 season. Prosecutors allege those samples tested positive for the designer steroid THG.
The two witnesses, Barry Sample, chief science officer of Quest Diagnostics, the company that analyzed Bonds' urine, and Dale Kennedy, who collected the sample, were necessary to establish that Bonds' samples were handled properly and can be used as evidence.
On Monday, Bell testified that Bonds told her he used steroids and became verbally abusive toward her at the end of their nine-year relationship.
The greatest hitter of his era threatened "to cut my head off and leave me in a ditch," she said. "More than once."
She said Bonds told her "he would cut out my breast implants because he paid for them."