The day Kevin De Bruyne left Chelsea, no one thought he would be returning to English football as one of the most creative midfield players in Europe.
The same with Mohamed Salah. When he was sold to Roma, it would have been a brave individual who predicted he would come back a striker with 30, maybe 40 goals a season in his tank.
So, while there is no shortage of folk crowing that Jose Mourinho made terrible mistakes in letting them go, few have much evidence beyond hindsight.
It may be argued De Bruyne and Salah were considerably better players than they showed and that maybe the manager, and the club, should have persevered with them — but they had not revealed anything like the excellence that is apparent now.