"He was just following up after my official visit last week," Shackleford said. "Since February I've grown a close relationship with Coach Spencer, the Duke program, Coach Roof and a few players. I felt very comfortable up there."
Next up on the 6-2, 212-pounder's visit list is Vanderbilt, and it's starting to sound as though a final decision from Shackleford could be nearer than most people thought.
"I think my decision is going to be between Vanderbilt and Duke," he said Thursday. "Really football is football. Wherever I go, I'm going to prove to myself I can play. But I'm also trying to think about the long run, and which degree will take me the furthest."
Shackleford is one of several marquee official visitors expected in for what could be Vanderbilt's most important recruiting weekend of the winter. Also expected in are tight end Jonathan Massey (Gautier, Miss.) and lineman Mike Berry (Brentwood, Tenn.), as well as a host of already committed players.
Though Shackleford had effusive praise for Duke last week, Vanderbilt remains a strong contender for the three-star linebacker's services.
"I like Vanderbilt," he said. "Over the last few months I've grown into a close relationship with Coach David Turner. He's shown me a lot of love.
"Just as Duke did, he stressed the importance of me coming up. They both tell me that I can be an impact player on this year's recruiting class, and that I can be the vocal leader. I can see that happening.
"I did have some other visits set up, but I think after this weekend I might go ahead and end it. More than likely I'll have a decision by next week."
Georgia had previously been a possibility for Shackleford, but the Bulldogs have now backed off. "I don't have any hard feelings about that," he said. "I understand, recruiting is a business." South Carolina has an official visit tentatively scheduled for Jan. 20, but the way he talked on Thursday, it might not happen.
"Next week I'm going to sit down with my counselor and my head coach and my parents, and we'll figure out the pros and cons of each school, and we'll go from there."
Shackleford made an 1130 on his SAT and has a 3.3 grade average, so the academic rigors at either school should pose little difficulty for him.
Total Access Pass members can access film of Shackleford by accessing his Scout.com profile.