Instead, Sullivan spent Wednesday and Thursday manning Birk's center position with the first-team offense after 2007 undrafted rookie Dan Mozes took most of the first-team reps at center on Monday and Tuesday.
"The amount of reps, that's all up to the coaches," Sullivan said. "My only expectations coming out here are to learn the offense, get better, communicate with the older guys and learn from them."
Sullivan said he wasn't intimidated lining up next to Pro Bowl guard Steve Hutchinson and preferred to focus on his job rather than who was wearing the purple jersey next to him.
"When you look at it from the outside perspective, it's pretty cool, but when you get in there and you're playing next to those guys, you can't be wowed by any of those guys around you. You've just got to go out and do your job," he said.
With the center making the calls on the offensive line, it might be a difficult spot for a rookie to get accustomed to early in the process. However, Sullivan believes that the rookie minicamp the Vikings held the weekend after the draft helped immensely with their progress in this week's organized team activities (OTAs), which had about 97 percent attendance on Thursday.
"I think having that helped a lot," Sullivan said. "Everything went a lot slower there and we kind of got a basic knowledge with that. There was a lot going in, but at the same time the coaches do a great job teaching it and the older guys help us along. I know we're making mistakes here and there, but I know it's been pretty smooth so far."
The three-year starter at Notre Dame may have had a bigger transition last year, when his veteran Irish team struggled and draft analysts saw a drop in his play with two young guards surrounding him. The Vikings figured a down season in 2007 decreased Sullivan's stock enough that Minnesota was able to select him despite only having five draft picks, including one in the first four rounds.
"Looking back on draft stock now, who cares? I'm in a great place," Sullivan said when asked about the changes on Notre Dame's offensive line in his senior campaign and how that might have affect him. "I'm with a team that I love playing with, so I'm not going to think about that. It was just a young team overall. Those young guards at Notre Dame, you just watch – they're going to be a ton better this year. They've got a lot of experience under their belts and they're going to be an improved team. As for last year, it was a young team across the board."
Ironically, he figures he may have to learn the guard position in Minnesota in order to add to his NFL value. Although he didn't play guard at Notre Dame, the former high school Parade All-American has practiced there occasionally, both with the Irish and the Vikings.
"With the numbers that NFL teams carry, you have to learn to play multiple positions and I've done some guard work in drills," Sullivan said. "I don't know if I'd get any reps in the team settings yet, but I've done a lot of work with the right-hand, left-hand stance for playing right and left guard in the drills."
For now, he's just trying to pick up the offense as quickly as possible.
"It hasn't been much different than learning any offense before. There is a lot of different terminology used in the game of football, but the concepts are basically the same, so you've just got to learn the terminology and communicate," he said.