Imam had suffered a calf injury on the first day of play and a statement was put out by the Pakistan side that the left-handed batter's involvement for the remainder of the Test would be subject to medical opinion.
The visitors folded for just 110 in the first innings with Imam not coming out to bat, and the opener did not appear in the second innings either as Pakistan went down by 194 runs to lose the series with a game to spare.
The series defeat has seen drastic action being taken by the PCB with seven players, including Imam, sent home ahead of the final Test while white-ball head coach Mike Hesson will take over from Sarfraz Ahmed, who was also sent home.
"The Imam injury is a big question mark, and a deep disappointment," Aaqib said in an interview with Pakistan broadcaster Geo "Players in the past used to get injuries, but they used to put on casts and still tried (to play). We'll take action against this.
"How is it possible that a pulled muscle ruled you out of batting in both innings? He should have tried and fought. He'll have to face an inquiry; I can't say he faked it, but a muscle pull like that cannot stop you from batting altogether."
Aaqib then explained why the PCB felt the need to overhaul the squad while on tour, saying thy send a message to the recalled players, while blaming the team management for what he viewed was flawed team selection.
"Two Test matches have come and gone and the team has not competed in any way," Aaqib said. "There's one Test still to go. The (the team management) had a pace allrounder available, a second wicketkeeper, a fast bowler in Ubaid Shah.
"But those decisions were not being made. I spoke to the captain (Babar Azam) and coach and asked them to put Ubaid in because the other bowlers (Mohammad Abbas, Mohammad Ali and Khurram Shahzad) are all similarly paced.
"No batter in our top seven bowls. We should have included an allrounder, but most importantly, get in Ubaid Shah, who bowls close to 140kph. One fast bowler changes the composition of your attack."
Pakistan's new Test bowling coach Ashley Noffke says the management are just looking 'add positivity' into the squad ahead of third and final Test against England that starts in Birmingham on Wednesday.
Former fast bowler Shoaib Akhtar reveals the Pakistan Cricket Board (PCB) has completely lost faith in the Test team and is looking to rebuild the squad with younger players.
Pakistan interim Test coach Mike Hesson admits the "last couple of days have been challenging" but says the players are used to "chaos" ahead of the third Test against England next week.
Pakistan have made drastic changes ahead of the final Test against England, dropping seven players and releasing head coach Sarfaraz Ahmed and assistant Umar Gul after a disastrous series so far.
