Amir was banned for five years for his involvement in the 2010 spot-fixing scandal in England. He returned to all formats of the game in 2015 but announced his retirement from Tests at the age of 27 after having played 36 Tests with 119 scalps in his chequered career.
“He (Amir) had five years out of the game...In those five years, he didn't do anything. His body was not up to the rigours of day in, day out Test cricket,” ESPNCricinfo quoted Arthur as saying.
“We pushed him as much as we could during the England and South Africa series because he is such a good bowler whom we wanted during those tours. We've tried everything we possibly could with Amir. He could have managed those five years better. He'd be the first one to acknowledge that. But I understand where he was in his whole life, so it was a tough period for him. I understand all that," Arthur added.
Arthur felt Amir would have been one of the best Test fast bowlers in Pakistan's history had he not lost those five years to the spot-fixing ban.
“The Amir hype all those years ago was justified because he is a quality bowler. When the ball swings there's not much better. But he's not the bowler now that he was in 2009 and 2010. He was different, his body was different,” he said.
Arthur said the management had tried to ease Amir's workload over the past year, and experimented with the possibility of making him an overseas-only bowler.
“Of course there was (a possibility Amir would only play away). We managed him through the South African series. He didn't play any Test cricket during the UAE last year. That was part of his management, and we started putting that in place because we wanted him for the South African series."
Amir finished as the most prolific Pakistan bowler at the recent World Cup with 17 wickets, which only six bowlers bettered, and Arthur said the team will now have a "rejuvenated" limited-overs bowler in him.