With both Rio Ferdinand and Nemanda Vidic absent, Smalling has the opportunity to get his second run out for the club against Philadelphia Union on Wednesday.
It represents a rapid rise for Smalling, 20, who 18 months ago was playing non-league football for Maidstone.
The former Fulham stopper partnered fellow central defender Jonny Evans in the recent 3-1 victory over Celtic and credited the United players for helping him adjust to the higher level.
Smalling said: "The tour has been a really enjoyable experience so far. It was great to meet everyone.
"I have spent quite a bit of time with Wes [Brown] and Jonny [Evans].
Brown believes Smalling has all the right attributes to succeed at Old Trafford.
"Chris is a great lad and has fitted in brilliantly," he said. "He has been training really well – he looks very fit and sharp. I am sure he will be ready and raring to go for the start of the season."
Brown also suggested that United are now taking seriously the threat posed by rivals Manchester City, stating that the derby clash with City is the biggest game of the season.
Asked what is the first game he looks for when the fixtures are announced, Brown said: "There are a few – City, Liverpool, Chelsea and Arsenal.
"But for me City is the big one, then I would say Liverpool then Chelsea."
By Jamie Bowman
