There is no timetable for his return, but Shepard, who was carted off the practice field Wednesday and had the MRI on Thursday, said he expected the team to take it on a day-by-day basis.
McAdoo also sounded optimistic after getting results from the MRI and additional tests.
"Yeah, nothing with it," McAdoo said. "Injuries are an unfortunate part of the game. We take them all serious, and we look forward to getting [Shepard] back when we can get him back."
The injury occurred while Shepard was running a route during a non-contact drill. He noticed the turf shift, rolled the ankle 90 degrees and felt a pop. He wasn't able to put any pressure on the affected area, and was taken off the field on a cart but denied there were tears despite excruciating pain.
"I was kind of screaming, but that is because I had never felt that pain before," Shepard said Friday.
It was the first time he had ever rolled his ankle. The unfamiliarity with this kind of injury contributed to the initial scare.
"Yeah, at first I was pretty worried," Shepard said. "I had never rolled my ankle like that before, and I felt it pop. That was the main thing that pretty much scared me. The initial pain wasn't too good. But now we're moving along and it has been pretty good now."
The initial diagnosis was a sprained ankle, but the Giants wanted to wait until the swelling went down for a final verdict. Although he wore a boot after the injury, he was walking without support and worked out on an underwater treadmill Friday.
Shepard is coming off a promising rookie season in which he ranked second among rookie receivers with 65 catches for 683 yards and eight touchdowns. He's expected to play a significant role this season working alongside Odell Beckham Jr. and Brandon Marshall.
According to ESPN Stats & Information, Shepard was on the field for 95 percent of the Giants' offensive snaps last season (964 of 1,019), which was the third most by an NFL rookie receiver in the past decade.
"Shep is a good player. He had a tremendous offseason," McAdoo said. "He was having a good camp, and when he gets healthy and can step in there, we'll welcome him back."
Giants will miss Shepard's versatility
Field Yates and Herm Edwards share how much WR Sterling Shepard's injury will impact the Giants if he misses time.