A back injury to Hasan Ali will potentially keep him out of cricket for a prolonged period, capping off a difficult few months for the pacer who, until 2019, was an essential component of Pakistan's pace attacks.

In part, Ali's form and injuries resulted him in missing out on a central contract on Wednesday. And now it has emerged that the injury, identified as an intervertebral disc protrusion, could even, in the worst case, lead to surgery.

Earlier last season Ali had suffered a back injury during the opening round of the Quaid-e-Azam Trophy in Lahore, following which he underwent a seven-week conservative rehabilitation at the National Cricket Academy. He was declared fit for the final round of the tournament, only to suffer a fresh injury - a rib fracture - in November that ruled him out for a further six weeks. He consequently missed Pakistan's international commitments in the season, but returned after another spell of rehab ahead of the PSL. He didn't look at his best in the tournament, picking up eight wickets in nine games at an economy rate of 8.59 for Peshawar Zalmi.

But continuing pain in his back led to scans which confirmed the problem in the back had flared up again, with symptoms consistent with a lumbar herniated disk. With guidance from the PCB's medical department, Ali consulted a local neurosurgeon and engaged an Australian physiotherapist for recovery. The PCB had intended to fly the bowler out to Australia, but with globally enforced lockdowns and travel restrictions in place, all consultations are currently being carried out via a video link. Ali, meanwhile, is on medication and is awaiting a decision by his doctors on whether he needs to go for surgery, or whether a more conservative treatment will suffice.

The flare-up will lead to questions about whether Ali should have returned to the PSL, though Misbah-ul-Haq, Pakistan coach and chief selector, insisted that Ali had played only after ticking off all fitness boxes.

"He cleared all protocols before playing PSL .. he was declared fit," Misbah said. "He was fully prepared, bowling 50 overs per week in his rehabilitation and playing practice games as well. Back injuries are always tricky. It can be aggravated at once by even a stumble in the field and in his [Ali's] case, it didn't recur (during his fitness tests), which is why he was given the go-ahead. He is being examined and taken care of."

Ali is the latest in a growing list of Pakistani fast bowlers who have seen their careers interrupted - and eventually derailed - by injuries, a trend which is, in private circles, leading to more questions being asked about the capability of the board's medical department.

Injuries aside, however, Ali's form had dipped considerably even before the injuries, not least at last year's World Cup where he cut a mere shadow of the figure who was central to Pakistan's Champions Trophy triumph in the same country in 2017. Misbah, however, still believes in his importance.

"We feel for him," he said. "There is no time limit for this return, but we are determined to bring him back. He is an absolutely great guy, a hard working athlete and fights for the team. This is why we are with him and the Board is giving him full support in every way possible. He was very well taken care of earlier when he got injured and even now we are standing behind him. We will make sure he will get proper treatment, and rehabilitation will be carried out to get him fit as soon as possible."

Over the years, Pakistan have invested significantly in Ali as he became an automatic pick across formats under previous head coach Mickey Arthur. He made a flying start to his international career after making his Test debut in 2017, but suffered a slump in form last year and broke down with injuries. He last played for Pakistan in June 2019 and then missed almost the entire first-class season at home (playing one first-class game only) last year.