The left-arm fast bowler was seen stretching out his right knee as Pakistan beat Test debutants Ireland by five wickets during a one-off match in Malahide, Dublin concluded last week.
Pakistan bowling coach Azhar Mahmood suggested Amir had suffered a recurrence of a “chronic” problem.
But head coach Arthur, speaking to reporters at Lord’s on Tuesday, had no qualms about the fitness of Amir.
“He’s perfect, 100 percent,” Arthur insisted. “He’s fine he’s ready to go.”
As for Amir, missing Pakistan’s final warm-up match ahead of the two-Test England series, last weekend’s drawn match against Leicestershire, Arthur added: “It was his rotation. (Mohammad) Abbas sat out the first (tour) game, Hasan (Ali) sat out the second, so he sat out the third.”
Amir was the hottest property in world cricket after bursting on the scene as a teenager in 2009 and at 18 he was the youngest bowler to have taken 50 Test wickets.
But his world was turned upside down in 2010 when he became involved in a spot-fixing scandal after deliberately bowling no-balls during the Lord’s Test against England — an incident that would eventually see him sent to prison by an English court and given a five-year ban by the International Cricket Council.
Amir’s first 14 Tests saw him take 51 wickets at just a fraction over 23 apiece, figures that had him on course to be an all-time great.
But the 17 Tests since his comeback two years ago have seen him take 49 wickets at a more expensive average of 34.91
Amir and Pakistan for that matter have not been helped by the fact that those 17 Tests since 2016 have also seen 16 catches dropped off his bowling.
The stigma of his spot-fixing exile has started to fade, with Amir playing for Pakistan during their 2-2 draw in a four-Test series in England two years ago.
He also starred for Essex as they won English domestic cricket’s first-class County Championship title last season.
Now the 26-year-old Amir is set to be the leader of an inexperienced Pakistan attack.
England, who didn’t manage a single win during their recent seven combined Tests in Australia and New Zealand, collapsed to 58 all out in Auckland in March as Kiwi left-arm quick Trent Boult took six wickets.
– ‘Finest exponent’ –
“I think Mohammad Amir is the finest exponent of pace and swing when he gets it 100 percent right,” Arthur said.
“We’ve used that spell that Trent Boult bowled in Auckland. We’ve had a look at his lengths.
“We believe he (Amir) bowls incredibly well at left-handers and there will be three left-handers (Alastair Cook, Mark Stoneman and Dawid Malan) in the (England) top four.
“He’s ready, I just hope it goes really well for him because he’s been unlucky at times with the amount of dropped catches.
“He’s ready, he’s determined, he’s fit, he’s strong, he’s excited, he’s in a very good place at the moment.”
Arthur is unusual in having served as the head coach of three leading nations — his native South Africa, Australia and Pakistan.
But he was adamant he had no desire to replace Trevor Bayliss when the Australian steps down as England coach next year.
“No, I’m very happy,” Arthur said.
“I’d like to keep going with Pakistan for as long as they will have me because it’s unfinished business for us at the moment. This is a very young cricket team and I worry if we move on what happens to these guys.
“Their fitness regime is outstanding, they are training hard and they are enjoying their cricket
“I’m very, very happy with where I am at the moment,” he insisted. APP/AFP