Napoli forward Osimhen suffered a serious injury to his eye socket after collision with Inter Milan defender Milan Skriniar earlier this month. The 22-year-old required surgery, including six plates in his face, after his eye came out of its socket in the clash.
Osimhen was ruled out of action for the next three months, which would include the AFCON.
But Ighalo, who recently returned to the international fold after an early retirement, says he is hoping for a miracle to see the youngster in Cameroon.
"I spoke to him after his surgery to wish him well, and to tell him that this is one of those things that happen," Ighalo told ESPN. "I am praying by God's grace for him to recover. We need Osimhen at the Nations Cup.
"He is young, he is a fighter and he will come back stronger than before and make it to the Afcon. We will see him there doing well as he has been doing because this is his time and he needs to shine."
Ighalo was only recently persuaded to make a return to the Nigeria national team, and tells ESPN that pressure from Nigeria coach Gernot Rohr proved too much to resist.
The 32-year-old announced his retirement from international football the day after helping Nigeria claim bronze at the 2019 Africa Cup of Nations in Egypt, but found himself running out in green and white again as the team battled to a nervy 1-1 draw against Cape Verde this month.
That comeback was the result of months of sustained pressure from Rohr, who had made it clear since the forward announced his retirement hat he would have preferred to see him carry on.
"Since I resigned in 2019, the coach has been in communication with me to come back," Ighalo said. "Game after game he would call me and ask me when I am coming back. The pressure was a lot."
In recent months, that pressure intensified with NFF President Amaju Pinnick joining in and the forward said that in the end, he could not say no.
"I kept telling him I don't think I want to come back but the pressure was too much and then the NFF President joined in," Ighalo said.
In making the decision to return, Ighalo said he did it because Rohr stood by him in 2018 when he faced backlash after a less than impressive World Cup performance.
The former Manchester United player said: "I decided to come back because Coach Rohr was there for me in 2018. I was getting death threats after the World Cup and I said I was not going to play again for Nigeria.
"He called me and said even the best players in the world miss chances. He told me to forget about what they're saying, that when I come back and start scoring, the same people will still come back to say good things. He assured me that he trusted me and believes in me.
"He gave me confidence. I needed him then and he was there for me. So now he was calling me, messaging me to come back. He needed me now, would I turn him down? Game after game, he has been asking me. So I said, Okay. If he was there for me, and he needs me now, I have to be there for him too.
"It is my country. It's a privilege to play for Nigeria. So it was my decision to come back even though the pressure was a lot and I'm happy I'm back."
Having returned to the team where he was once the lead striker, there were questions about what his position would be now, with Osimhen now established as the main forward.
Ighalo says those questions were unnecessary, as Osimhen was and would remain the top striker: "People say I'm coming to take the position but no, I'm not going to do that.
"Before I left the national team, I personally called Osimhen and said I'm leaving, this position is for you and if you work hard you're going to rule Nigeria for a long time. I'm happy seeing him doing well and I'm here to support him.
"And before I came back, I told the coach 'Osimhen is the number one striker, I will just support in whatever way you want me to support' and I'm here to do that."
As a sign of his respect for his successor, Ighalo turned down the chance to reclaim the number nine jersey, despite being offered the shirt.
"A top NFF official told me I could have the number nine jersey back and I told him no. I had left it. Osimhen is using it now and coming back, I'm going to play with any jersey number.
"I told them to give me any jersey available. I can play with my bare skin for Nigeria, I'm a patriotic Nigerian. If it means me playing without a shirt in this team, I'm going to play. It's not the shirt that score the goals."