Richard Dieter, executive director of the Death Penalty Information Center, said Delaware death row inmate Steven Shelton was granted a request in 1995 to donate a kidney to his mother while in prison, though he was not facing imminent execution like Phillips.
"This step by the governor puts it into a more normal discussion of an inmate, without any security problems, can help save another person and is that the right thing to do," he said. "With 24 hours to go before an operation had to be carried out, it definitely gets in the way of that process."
Vital organ donations raise larger ethical issues and have so far not been allowed during U.S. executions, Deiter said. They have occurred in China, he said.
Dieter, whose group opposes the death penalty, added: "If the whole idea is to save a life, there's one life to be saved simply by not executing the person at all."
Phillips made his request after the governor denied him mercy and Phillips had exhausted his other legal options. His attorney said it wasn't a delay tactic but an attempt to do good.
The state had left it up to Phillips' family whether the organs would be harvested after his death.
Phillips had been moved to Ohio's death house Wednesday, but a prisons spokeswoman said he was being returned to death row immediately after Kasich's stay was issued to await the assessment's findings.