Mohsin and Afridi confirmed that Gul had informed them that he was not 100 per cent fit for the mega-event because of his shoulder injury.
"It is a good gesture from a senior player and sets the right precedent for others to follow in future," Mohsin said.
"Umar told us that he was not 100 per cent fit in the camp and required more time to gain his full rhythm and fitness and that we should consider including someone else in his place for the World Cup," the chief selector added.
"I am 70 to 80 per cent fit at the moment but I do not think that is enough to play in an international event which demands 100 per cent fitness," Gul said.
"Everyone including the coaching staff was keen to have me on the team considering the fact that my bowling was of some help during the previous two editions of the World Twenty20. Majority of the stakeholders believed that I can regain fitness in ten to fifteen days but that is something that was entirely based on hope." he said.
Gul said he did not want to hurt the team's chances by hanging on to his place despite not being fully fit.
"It was a risk that I think the country and the team was not in a position to afford. I think you can only stake a claim when you feel you are in a position to deliver. I may be able to regain fitness or could never have been in a position to bowl a single delivery in West Indies . That would have been a blow to the team's chances," Gul said.
All-rounder Yasir Arafat was also ruled out of the World Cup because of a calf muscle injury and Muhammad Sami and left arm spinner Abdul Rehman were named replacements for the two unfit players in the Pakistan squad.
The ICC World Cup technical committee on Tuesday approved the changes in the Pakistan team.