Due to the international break, Jose Mourinho has called up a number of young players to train.
And they've an impression on the United veteran.
"It's great to see their energy," Smalling told MUTV's Mark Sullivan. "It reminds you of when you were that young and you wanted to come in. We've had quite a lot of young players in and it's nice to see. There must have been at least seven, eight or nine of the young ones."
"Again we'll train with them tomorrow – I think we're playing a bigger [sided] game. It gives every one of them an opportunity to see that pathway through [to the first team]."