Ighalo, 30, joined United on transfer deadline day last month from Chinese Super League side Shanghai Shenhua.
But he has yet to train with his new teammates since arriving from the Far East.
Ighalo was initially left out of the Red Devils' warm-weather training camp in Spain over fears that border restrictions amid the coronavirus may not allow the Nigerian international back into the UK should he leave.
Ighalo has been training with Manchester-based performance coach Wayne Richardson at the GB Taekwondo Centre in Manchester.
But he arrived at Carrington on Sunday morning, chauffeured in to train with his new teammates for the first time, reports the Mirror.
Manchester United (@MUnitedFR) February 16, 2020