Ladouceur, a 14-year veteran, could not recall ever being flagged for such a penalty.
With three seconds remaining, Ladouceur's penalty moved a potential game-tying field goal attempt from 47 to 52 yards, and Brett Maher's kick hit the left upright, leaving the Cowboys with a loss -- 20-17 against the Washington Redskins -- and at a loss.
"I just adjusted down so I could put my hands on the bottom of it, so I could snap it in the right direction," Ladouceur said. "Exact same thing I've been doing for 14 years ... I'm not even trying to get him offside. I know the situation. Just too bad."
Coach Jason Garrett said he was told that Ladouceur moved the ball in a way that prompted Jonathan Allen to jump offside. Garrett could not recall the last time he saw that called as a penalty.
"Once? Twice? Not very often," Garrett said.
On Twitter, Al Riveron, the NFL's director of officiating, said the "illegal ball movement by the center causes the defense to come across the neutral zone and contact a lineman."
Ladouceur -- the longest-tenured Cowboy, having joined the team in 2005 -- said he went through the same pre-snap routine he has followed his entire career.
"Never had that before," Ladouceur said. "I do the exact same thing every time, so when that happens, that's what I was telling the ref: 'I do the exact same thing. Yeah, the guy jumped.' That's what I thought."
Ladouceur said he puts one hand on the ball, then a second and lays it down so he can snap it accurately. Entering Sunday, he was perfect as a snapper, with clean snaps on 924 punts, 572 point-after attempts and 419 field goal tries.
What is Ladouceur's understanding of the rule?
"As long as I don't pick up the ball," he said. "The ball was on the ground the whole time."
Maher had made 16 straight field goal attempts prior to his miss. He said he pulled the kick slightly, and the wind might have played a part as it was coming down.
"That penalty had zero impact on the result of that kick, I can promise you that," Maher said. "L.P. and [holder Chris Jones], like they've done all year, they made my job easy, and it was the same in that situation. Yeah, I felt like I was very capable of making that kick. Just didn't get it done."