KARACHI: Paceman Mohammad Amir's comeback after his ban for spot-fixing has been halted by a hamstring injury which will take up to three weeks to recover, his agent said Friday.

The left-arm quick suffered the injury on his 23rd birthday -- the second day of the Patron's Trophy Grade II final in Karachi on Monday.

Amir's agent said his injury had been assessed by a Pakistan Cricket Board (PCB) medical panel.

“Dr Sohail Salim of the PCB has confirmed that Amir's hamstring is a grade II tear which takes 7-22 days for proper recovery,” his agent told AFP.

Amir can resume bowling on May 4 onwards, meaning he will be available for the Super Eight Twenty20 tournament to be held in Faisalabad from May 11.

Amir had taken 22 wickets in the four matches prior to the final of the Patron's Trophy, which is one level below first-class.

It marked an impressive return since the International Cricket Council relaxed his five-year ban for spot-fixing in January this year.

The decision came after PCB requested the ICC to allow him to play domestic cricket a few months before his ban officially expires in September.

Amir, along with new-ball partner Mohammad Asif and then-captain Salman Butt was banned for delivering pre-arranged no-balls in return for money during the Lord's Test against England in 2010.

The PCB said it asked for Amir's ban to be relaxed only after the paceman pleaded guilty and completed all conditions demanded by the panel which banned him in February 2011.

Amir's international ban expires on September 2 this year after which the PCB will decide on his comeback to the national team.

Amir has said he is aiming for a gradual return to international cricket, only after gaining full rhythm in bowling and attaining full fitness.