Lazio and BVB face eachother in the Champions League this week, which will see Immobile face his former teammates at Dortmund.
Riedle said: "Immobile at Dortmund was unlucky, it wasn't the right time. He will want to show that that year it wasn't the fault.
"(Erling) Haaland? He is already a complete striker, he will have a great career.
"The teams are the same but Borussia are better off, so I think they have a few more chances to win."