The series resumes in New Jersey Thursday night with each team having won twice.
Nieuwendyk missed the first four games of the series and has played just three shifts since suffering a back or hip injury in Game 6 of the Eastern Conference finals. He did not travel with the team for Games 3 and 4 of the Stanley Cup Finals, but took to the ice Wednesday at the Continental Airlines Arena.
Just as the Devils were beginning to work on the power play, Nieuwendyk returned to the locker room.
"I was pleased with the progress, I just don't think I'm where I need to be right now," he said. "I would say my status for tomorrow would be doubtful. They indicated to me at the beginning of this it would be a week-to-week thing. I think we're kind of treating it as an hour-to-hour thing."
While the 36-year-old Nieuwendyk left open the possibility of playing Thursday night against the Mighty Ducks of Anaheim, Burns was less optimistic.
"I would say that he is definitely very, very doubtful for tomorrow," the coach said.
Nieuwendyk and team officials still have not divulged the exact nature of the injury. But he made clear it continues to impede various aspects of his game.
"Whether it be faceoffs or anything, if I don't feel that I can do those things the way I can, then I don't want to be a liability out there," he said.
New Jersey could use his faceoff expertise. They have lost nearly two-thirds of the faceoffs in the first four games.
A veteran of four Stanley Cup Finals, Nieuwendyk called the injury the most frustrating moment of his 16-year career.
"The one year I got knocked out in the very first round, the whole (Bryan) Marchment incident, that was tough. But this is way above that," he said. "(The series) looks exciting from where I'm watching it and I would certainly like to be a part of it."
Burns refused to commit to a lineup for Thursday.
"I don't want to read into things and I don't want to get too excited," Rupp said. "I'll take it in stride whatever happens tomorrow."
The 23-year-old Rupp logged just over nine minutes in Monday night's 1-0 overtime loss. But at 6-5 and 230 pounds, he adds size to the lineup.
"It's all of our jobs to get in front of the goalie," he said. "I might have an easier time with my size, but I think as a team, all of us need to do it."
The Devils appear close to getting back another player with size. Right wing Turner Stevenson, who has missed five straight and eight of the last nine games due to a groin injury, skated hard in practice Wednesday.
"If it feels like this tomorrow, I'm sure I'll play. I felt great today, pain-free," he said. "It's the hardest I've skated in 10 days, two weeks. If it reacts as it has, it's usually not that good tomorrow, so we'll see in the morning."
After winning the first two games on home ice by the same score, 3-0, New Jersey fell in overtime in both the third and fourth contests in Anaheim.