Cahill, who was at Stamford Bridge throughout Salah’s brief stay, believes a number of factors played a part.
“Speaking from experience, you’re coming into a quality dressing room and it is a very difficult club to break into, to stay here, maintaining a position season after season.
“The competition is always there. Chelsea buy players so you’re always under threat. The club make the decisions and that’s that. But players make the decision, too. If they’re not getting enough game time, they look to leave.
“Sometimes it’s difficult if someone wants to play all the time and doesn’t, what do you do in that situation? I saw the ability Salah had because I trained with him a lot.