The 19-year-old completed a medical with the Red Devils last month, despite picking up a knee injury at the end of his time with former club Porto.
Dalot, who set United back £19m, had been using the crutches to get around but has now been given the green light to operate without them.
According to The Sun, Jose Mourinho now intends to use the Portugal Under-21s international in the first set of United's pre-season fixtures.
An Old Trafford source is quoted by the publication as saying: "Diogo is now off his crutches and can take part in pre-season when it starts. He has been making solid progress and the conditioning team will take a closer look when he returns later next week.
"There aren't any worries about his future fitness. It was just one of those injuries, hence no worries with the medical."
United's first pre-season game is against Club America at the Phoenix Stadium in Arizona on July 20.