The former Phra Buddha Isara was a no-show at the Criminal Court on Thursday. He was due to attend to enter a plea for his role in the anti-Yingluck Shinawatra government protest in 2014.
Suwit Thongprasert, 59, as he is also known, was rushed to a hospital for emergency treatment of a herniated disc as soon as he was released from Bangkok Remand Prison late on Wednesday, said his lawyer, Thirayut Suwankesorn.
The ex-monk was granted bail after the Criminal Court accepted a lawsuit from the prosecution in which he was charged with illegally detaining two plainclothes policemen during a Feb 11, 2014 protest on Chaeng Watthana Road. He was released later that night.
Mr Thirayut said his client, whose symptoms flared up while in detention, would have to spend some time at the hospital for treatment and physical rehabilitation.
The defence lawyer handed over a medical letter to the court on Thursday and asked for a rescheduling of the hearing. Subsequently, the court postponed it to Oct 8 at 9am.
Mr Suwit was arrested at his living quarters in a high-profile raid at Wat Or Noi in Nakhon Pathom's Kamphaeng Saen district in May as part of a police crackdown on rogue monks.
The former Phra Buddha Isara was defrocked before he was put behind bars. He denied the charge during the police investigation. The ex-monk was also indicted on a charge of insurrection for his role in the "Bangkok shutdown" demonstrations to oust the Yingluck Shinawatra government. He also pleaded not guilty to that charge.
About 20 followers of the ex-monk turned up at the court to provide moral support. They dispersed shortly after they learned that he was being treated. The former monk was granted bail on condition that he does not leave the country without permission.
On Aug 15, the Corruption Court agreed to hold separate trials for the two lawsuits filed against the former seven monks and three lay people in connection with the alleged embezzlement of temple development funds.
The first case involved the former Phra Phrom Dilok and his ex-secretary, who is the former Phra Atthakit Sophon, for alleged abuse of authority in connection with the fund embezzlement. The two did not apply for bail.
The other five monks include the former Phra Phrom Sitthi and three lay people accused of money laundering in relation to the temple embezzlement fund. The latter eight defendants applied for bail but the court rejected the requests.