Sky Sports says the striker, 32, currently plays for Saudi Arabian side Al Shabab and is the top scorer in the league this season with nine goals.
He moved to the Middle East after his loan spell at United, from Chinese side Shanghai Shenhua, came to an end earlier this year.
He scored five goals in 23 games for the Red Devils.
And he would be open to a move to St. James' Park.
Al Shabab have reportedly spoken to Ighalo about a potential move with Eddie Howe's 19th-placed side in desperate need of new signings.