Eriksson said: "Once Rooney started to play, you always had to pick him. If some players are 10, Wayne is 50. Emile was also injured a lot towards the end of my time with England.
"When he was fit and playing for England, he was one of the best on the pitch.
"The games he played for England under me, I think he did very well, especially when we beat Germany 5-1.
"But when he got injured, he only played now and then and ended up on the bench a lot at Liverpool. But that's football and it happens now and then."
Eriksson is happy to see Heskey has rediscovered his form to earn an international recall.
He added: "He deserves to do well as a football player and as a man. As a man he is 10 out of 10.
"I don't know why some people didn't think he was so effective but that can affect you as a player, of course it can."