Mohammad Amir was forced from the field with a "chronic" right* knee injury late on the third day at Malahide, a development that will be the cause of some anxiety within the Pakistan camp not only as they look forward to the end of this Test but two more against England.

Amir first went off the field after a three-over opening burst, with what appeared to be a slight limp. He came back out soon after, however, and though he was walking gingerly, he eventually came on to bowl again. Two balls in, however, he got into a discussion with captain Sarfraz Ahmed and though it looked as if Amir was suggesting that he finish his over, he eventually walked off. Medical staff will assess the injury after treatment overnight before deciding if he is fit to take part in the rest of the match, though initial assessments suggest it isn't serious and that he could bowl tomorrow.

"He has got a chronic knee problem which has slightly flared up," said Azhar Mahmood, Pakistan's bowling coach. "Hopefully, he will be okay tomorrow to bowl for us. He's having treatment and hopefully tonight we will do a bit more treatment, tomorrow morning, ice as well, so he will be fine."

According to Mahmood, it has been a recurring problem for the fast bowler and it will do little to alleviate concerns about Amir's long-term future in five-day cricket. Amir has spoken of wanting to manage his workload in the future with the help of a rotation policy that allows him to sit out occasional Tests.

That concern comes from having bowled more international overs than any other Pakistan fast bowler since Amir's return to international cricket in January 2016, a return after five years out. And though it has been over six months since Pakistan's last Test and Amir has played plenty of cricket in between, this is now twice in two Tests he has gone off with an injury - against Sri Lanka in Dubai it was a problem in his right shin that forced him off.

"Yes, you can say that because unfortunately he came back after five years and since he came back he played every format for us," Azhar said. "We have to manage his workload as well so maybe that's a sign for us to in the future to see where he stands and we've got a bunch of young guys coming up and we want to have Test bowlers separately to the one-day and T20s, so we are working on that and hopefully we can come up with something."

Mahmood emphasised that keeping Amir in Test cricket is Pakistan's greatest priority.

"We want him to play Test cricket because he is our No.1 bowler and we want him to run in and bowl for us. Workload - I have seen a lot of fast bowlers and their body can't take it, so they just manage to play one format or two formats, but for him it's a concern for us but hopefully we will manage his workload in the future."

Frustratingly for Amir and Pakistan, the injury occurred just as he was bowling probably his best spell of the tour so far. He got more swing as Ireland followed on than he did in the first innings, though his luck had not returned - two more catches were spilled off his bowling in that burst, bringing to 16 the number of missed chances off Amir's bowling in his last 17 Tests.