Joined have marked Ighalo on a six-month advance from Shanghai Shenhua.
The Nigerian striker is relied upon to be in Ole Gunnar Solskjaer’s squad, for Monday’s excursion to Chelsea in the Premier League.
Solskjaer moved to sign Ighalo, after Marcus Rashford was precluded for as long as a quarter of a year with a back issue.
However, Scholes, addressing the UK Mirror, stated: “I don’t believe he’s marking as long as possible. I think his scoring record in China is awesome, however is it valid? I don’t have a clue.
“It’s acceptable to have an additional body, yet when you’re United, you need an additional body with quality, and he has that to demonstrate.
“He’ll bring something other than what’s expected. I don’t see him beginning numerous games.”