The 20-year-old victim, identified as Mahmoud Issa al-Jaziri, was hit in the head on February 14 after security forces attacked anti-regime demonstrators in Nabi Saleh, south of Manama, as they were marking the second anniversary of the uprising.
The Bahraini authorities have so far made no comment on Jaziri's reported death, but Bahrain's main opposition bloc al-Wefaq said the protester died in hospital early Friday after a week in a coma.
This is while, the Bahraini regime refuses to hand over the body of al-Jaziri to his family for funeral ceremony scheduled to lay him in rest, al-Alam reports.
Several protest rallies were held across Bahrain overnight in commemoration of Jaziri and condemnation of the brutal regime.
He is the third Bahraini protester killed in less than ten days. Another protester, Hussein al-Jaziri, 16, was killed on February 14 in the village of Daih, while Aminah al-Sayyed Mahdi, 35, died last Friday, a month after inhaling toxic tear gas fired by Bahrain troops at an anti-regime rally in Abu Saiba.
Bahrainis have been staging demonstrations since mid-February 2011, demanding political reform and a constitutional monarchy, a demand that later changed to an outright call for the ouster of the ruling Al Khalifa family following its brutal crackdown on popular protests.
Scores have been killed, many of them under torture while in custody, and thousands more detained since the popular uprising in Bahrain began.
Protesters say they will continue holding anti-regime demonstrations until their demands for the establishment of a democratically-elected government and an end to rights violations are met.