Ighalo retired from international after the 2019 Africa Cup of Nations, where he finished as top scorer.
One of the reasons he gave for his decision, was the stress of travelling between China and Nigeria.
Ighalo, however, moved to England in January, joining United on loan from Chinese Super League side Shanghai Shenhua.
This week, the 30-year-old extended that deal until January 2021.
The turn of events has made Ighalo to reconsider his availability for the Super Eagles.