Former Pakistan captain and Multan Sultans' player Shahid Afridi was ruled out of the remaining matches of the Pakistan Super League (PSL) 6 tournament on Monday after suffering a back injury during training.

A statement issued by the Pakistan Cricket Board (PCB) said that Afridi was training in Karachi for the upcoming matches of PSL 6 — due to be played in Abu Dhabi next month — when he experienced pain in his lower back.

Afridi was then examined by a doctor who advised him "complete rest", the statement added.

The former captain said he was "heartbroken as I was practicing and training really hard".

While expressing disappointment at having to sit out the remaining matches of the league, Afridi said his "best wishes, support and prayers are with the team to take the trophy".

He has been replaced by left-arm spinner Asif Afridi, according to the PCB statement.

Naseem Shah out for breaching protocol

Meanwhile, Quetta Gladiators' fast bowler Naseem Shah was also ruled out from the tournament for breaching Covid-19 protocols.

In a separate statement, the PCB said a three-member panel made the decision to "expel" Shah after he arrived at the hotel the team was supposed to assemble in with the result of a Covid-19 test conducted on May 18 — at least two days earlier than he was supposed to get tested.

According to the cricket body, all those travelling to Abu Dhabi for the tournament from Karachi and Lahore were directed to assemble at the team hotels in the two cities on May 24 with negative reports of PCR tests taken not more than 48 hours prior to arrival at the hotel.

"However, Naseem presented a PCR report from a test that was conducted on 18 May. Upon submission of the report, he was placed into isolation on a separate floor before being released," the press release said.

Commenting on the news, the head of PSL 6, Babar Hamid, said the PCB did "not take any pride" in releasing Shah from the tournament but "if we will ignore this breach, then we will potentially put at risk the entire event".

He thanked the Quetta Gladiators franchise for accepting the decision.

Hamid said the decision would "send out a loud and clear message to all involved in the remaining matches that the PCB will not compromise on any violations and will expel the player or player support personnel irrespective of his stature and standing in the game if they are found to be flouting the prescribed protocols or regulations".

The official said the onus for following the protocols was on all those participating in PSL 6 and the conditions had been "put in place for the health and safety of all involved as well [as] for the integrity and credibility of the event and the PCB".

The PCB announced last week that it had received all outstanding approvals and exemptions from the United Arab Emirates government for staging the remaining 20 PSL matches in Abu Dhabi.

The tournament was cut short in March with 14 matches played after seven people participating in the league tested positive for Covid-19.

At the time, the cricket board had said the decision had been taken out of consideration for the health and wellbeing of all participants in the tournament.