The 17-year-old wowed spectators with his performance for Wales in their emphatic win over the Republic of Ireland last week. Ampadu, who can play in midfield and defence, made seven first-team appearances under Antonio Conte last season.
Derby, managed by Blues legend Frank Lampard, attempted to sign Ampadu on loan but Sarri blocked the move. And Nevin thinks it was the wrong decision.
"To be honest if you look at the position, there's no way Chelsea promised him games this season," he said on BBC Radio 5 Live.
"There's no chance that was a possibility because if you look at that midfield now, Cesc Fabregas isn't even back.
"That's before you look at the (Danny) Drinkwaters and plenty more players like that.
"What, Ampadu walks on the scene and he can go and play in the midfield? Not a chance.
"So I think it would have been sensible for him to go out and have another year out.
"Maybe Chelsea's argument I would say now is they would like to win the Europa League
"They will need a lot of players for that and probably an entirely different midfield.
"So, how many games do you play in that between now and the end of the season?
"So you may get just about enough games, but playing every week in the Premier League?
"It's highly, highly unlikely."