Rohr says he does not plan to recall the 28-year-old striker to the national team despite his fine form.
“I know Simy very well, it was me who called him for the 2018 World Cup in Russia. He performed well at that competition, after which he played for some time in the Italian Serie B,” the Super Eagles boss told Europa Calcio.
“I have never forgotten about him and have always observed him, not just now that he is doing so well.
“However, the competition is huge: we have (Victor) Osimhen, (Kelechi) Iheanacho from Leicester and (Paul) Onuachu from Genk, who is very similar to Simy in terms of features and physical structure. Without forgetting (Umar) Sadiq and (Odion) Ighalo.
“So it is very difficult to be part of the Nigeria attack, we have very good players.
“As I said before, I have never stopped following his performances, but I believe that next year he must go and play in a club and in a team that is stronger than Crotone.
“It will not be equally easy, but he would already have a better chance of returning to the national team.”
Nwankwo has four caps for the Super Eagles of Nigeria and was part of the team that went to the 2018 FIFA World Cup in Russia, where he made two substitute appearances.