The Italian striker has been relegated to the U23 squad and told to find a new club by manager Jurgen Klopp.
"I do not want to reach the end of my career with regret not having done everything possible," the 26 year-old stated. "Two years ago I had everything I wanted, I thought I had enough.
"The last two years I've worked hard, but I have not had the expected results. I probably paid for the previous 23. But I'm calm, I've changed."