The centre-back has been filling in for Brazilian star Rafael, after he suffered a dislocated shoulder during the latter part of pre-season, on the right back.
“It fell on him really because Rafael got his early season injury and, in the Community Shield, we had to consider the height of the Manchester City team,” said Ferguson.
“We knew they were a big team so we had to balance out the aerial strength somewhere along the line.
“Bolton is another example of where the height of Smalling and his ability in the air is a big bonus for us.
“But we do have to be fair to him because we brought him here as a centre-back. His time there will come but the way he is playing at the moment there’s no need to change.”
