He told reporters that they had not expected Mr Chauvin to testify, saying the prosecution "would have chopped him down second by second" on the time he knelt on Mr Floyd.
Yesterday, Judge Peter Cahill turned down a defence request to acquit Chauvin, rejecting claims that prosecutors failed to prove Chauvin's actions killed Floyd.
Chauvin attorney Eric Nelso n called a police use-of-force expert and a forensic pathologist to help make the case that Chauvin acted reasonably against a struggling suspect and that Floyd died because of an underlying heart condition and his illegal drug use.
"This late disclosure is not the way we should be operating here", Cahill said.
Prosecutors also recalled Dr. Martin Tobin, a lung and critical care expert, to the stand to poke holes in a defense witness' theory that carbon monoxide poisoning from a police car's exhaust could have contributed to Floyd's death.
Jurors have only heard Mr Chauvin publicly defending himself once - when he was heard telling a bystander that he had to "control" Mr Floyd because he was a "sizeable guy" and "probably on something" in body camera footage played in court. Nelson said prosecutors have known for weeks that Fowler had meant to bring up potential complications concerning carbon monoxide and should have sought to include the tests, conducted during Floyd's autopsy, earlier.
With the trial in session, Minneapolis has been bracing for a possible repeat of the protests and violence that broke out last spring over Floyd's death.
A picture of George Floyd hangs on a fence outside the Hennepin County Government Center where the trial is beign held. That contradicted prosecution experts who said Floyd succumbed to a lack of oxygen from the way he was pinned down.
Yesterday, Dr. Fowler, a retired forensic pathologist, said it was possible that carbon monoxide ingestion from the tailpipe of the vehicle that Floyd was pinned on the ground near could have contributed to his death. He said Floyd's death had too many conflicting factors, some of which could be ruled homicide and some that could be considered accidental.
Mr Chauvin, 45, is charged with murder and manslaughter in Mr Floyd's death after the 46-year-old was arrested on suspicion of passing a counterfeit $20 at a neighbourhood market last May. Floyd's death spurred global protests against police brutality.
Protests and riots erupted across the United States in the wake of George Floyd's death. He also testified that Chauvin's knee was not applied with enough pressure to cause any bruises or scrapes on Floyd's neck or back.
Mr Floyd died previous year in an incident in which he was handcuffed by police with the officer's knee pressed on his neck.