Usman Khan, the Pakistan left-arm pacer, has been diagnosed with a stress fracture of the back in what is a career-threatening blow. The 23-year-old bowler, who had stunned Sri Lanka with figures of 5 for 34 in just his second ODI two weeks ago, will be out of action for at least six months as a result of the injury.

He picked up the injury after second T20 against Sri Lanka in Abu Dhabi, and missed the final game of the tour - the landmark T20 in Lahore. Medical screening confirmed lumbar-bone stress in his back. He had struggled with the same injury in the early days of his career, in 2013, after making debuting for Pakistan in T20 cricket. He has sustained back injuries twice before and missed a major chunk of season of 2014-15 as a result. "It is disappointing but this [course of treatment] will give him the best chance of recovering as quickly as possible," Mickey Arthur, the Pakistan head coach, told ESPNcricinfo.

Usman was brought into the ODI side for the Sri Lanka series after Mohammad Amir pulled out due to injury, and he made an immediate impact. His five wickets in the second game against Sri Lanka came within the space of 3.3 overs. The performance was a throwback to four years ago, at Gaddafi Stadium in Lahore, when he announced himself with five wickets for nine runs in 3.1 overs for Agriculture Development Bank of Pakistan.

Usman's injury is the latest in a string for Pakistan. Amir recently missed the ODIs against Sri Lanka before returning for the T20 series, and Ruman Raees Babar Azam and Imad Wasim are recovering from a wrist impingement, groin strain and knee injury respectively. When asked whether he was concerned by this sudden spate of injuries, Arthur said: "A little bit, but a lot of them niggles just needed a bit of rest and that is why we have put such a lot of effort in working on our bench strength."