The Los Angeles Times said it is not known at this point what is on the tape, and U.S. District Judge Susan Illston has yet to rule on whether she would admit the tape into evidence.
The surgeon, Dr. Arthur Ting, last week contradicted testimony by prosecution witness Steve Hoskins, Bonds' childhood friend and former business partner. Hoskins had said he and Ting had conversations about Bonds' alleged steroid use, the Times reported.
Hoskins says now he has discovered a tape he secretly made of a conversation with Ting. The Times said the tape is in the hands of the prosecution.
Meanwhile, Illston sent jurors home Monday after one became ill with a gall stone.
When the trial resumes, the prosecution is expected to put its last witness, leading anti-doping expert Don Catlin, back on the stand for more testimony, the San Jose (Calif.) Mercury News said.
Illston had wanted to replace the ill juror, but lawyers asked to have him kept on the jury because replacing him would reduce available alternate jurors to just one.
Illston said she would re-evaluate the situation Tuesday.
It was still unknown whether the defense planned to call any witnesses, the Mercury News reported.