Morrison will spend the campaign at Bramall Lane after leaving Swedish side Ostersunds at the end of last season.
"How will he do? I remember the first five months of one season when he was at West Ham, under Sam Allardyce," Neville said. "He'd got to a point where he was consistent, he was in the England U21s and was doing well.
"Then, over Christmas, he fell off it a little bit and it didn't quite happen for him after Christmas.
"It seemed to happen every year. If you can get 20 good games out of him, because he's that type of player anyway, and he wins two, three or four matches, then that would be a successful season.
"The main thing for Ravel is making sure he's there, he's fit and he's training and available.
"He has had a tough time and needs to settle. I hope Sheffield is that place for him."