A day after Conrad Murray's lawyers complained he was suffering a "slow death" in a tiny jail cell, the doctor was moved to a slightly larger one, his lawyer said.

Lawyers for the doctor convicted in Michael Jackson's death warned the Los Angeles County sheriff in a letter Wednesday that Murray was suffering possibly life-threatening and permanent injuries from almost a year in a 5-foot-by-7-foot cell.

Authorities transferred Murray to a 8-foot-by-10-foot cell of the Los Angeles County jail Thursday, "but it's not a good thing," his lawyer Valerie Wass said.

Murray was found guilty of causing Jackson's death on June 25, 2009, by administering a deadly overdose of sedatives and the surgical anesthetic propofol in what he told police was an attempt to cure the singer's insomnia.

The new cell has a solid door with only a small window, unlike the old cell that was open with bars that Murray could prop his long legs on when he stretched, Wass said.

"It's like being stuck in a closet and he's freaking out," she said. "He is feeling really isolated.

When Murray called his lawyer Wednesday, "he basically said 'Valerie, I'm dying, save me,'" Wass said.

Wass, who is leading Murray's appeal of his involuntary manslaughter conviction, and Michael Flanagan, one of his trial attorneys, will meet with jail officials soon.

The meeting will focus on Murray's health problems they blame on his limited exercise and small cell, Wass said.

"He needs exercise," she said. "You've got to get him out of that cell more than once a week."

The best solution, she said, would be for the sheriff to release Murray on monitored home confinement for the final year of his sentence.

Murray was sentenced to the maximum of four years in prison for causing Jackson's death, but California law requires him to serve just half of that behind bars.

Another law intended to relieve overcrowding in state prisons has Murray serving his time in the county jail, which Wass said was never designed for long term confinement.

Wass and Flanagan signed a letter for Sheriff Lee Baca Wednesday that they said was "notice of the life-threatening condition in which Dr. Murray currently exists."

"Correction of this intolerable situation is of extreme importance," they wrote.

Murray is held in a high-security section of the jail and isolated from the general prisoner population to protect him.

"Death or injury at the hands of another prisoner, however, is no worse than a slow death caused by a loss of circulation and atrophy resulting from inhumane confinement of a large man in a tiny space," the lawyers' letter said.

Murray -- jailed since November 7, 2011, when he was convicted -- is 6 feet 5 inches tall, but until this week he was confined in a 5-foot-by-7-foot cell, the letter said.

"If one were to keep a dog in a space just a few inches larger than the dog's length, for any extended period of time, contentions of animal cruelty possibly leading to prosecution would likely result," it said.

The sheriff's office did not respond to CNN's calls for comment.