Immobile was among senior players blamed for Italy's World Cup qualifying failure, but has shelved international retirement.
“It is true, I wanted to leave, but then I spoke to Mancini and I realised that I was still needed," Immobile told RAI Sport.
“When you are disappointed in such a way, you think a thousand things. However, with a clear head, I spoke to Mancini and it seemed that Italy still needed me.
“There is still the need for us veterans, who can help the younger players to develop and make the renewal process smoother for the Nazionale.
“As the coach said, what begins now is our comeback for the Euros and the next World Cup."