Letang's recovery timeframe was originally listed as week-to-week. He started to skate on his own before practices for about an hour at a time more than a week ago, Letang said.
"Still did not discuss [playing Monday] with the medical staff or the coaches," Letang said. "I just felt great in practice. That's the only thing I can tell you. ... [The recovery] was quicker than what we thought. So, I guess it went smoothly."
The Penguins (12-7-4) are 4-1-3 without Letang, who returned to the top defense pair with Brian Dumoulin during line rushes Sunday. He was also part of the top power-play unit with forwards Evgeni Malkin, Jake Guentzel, Bryan Rust and Patric Hornqvist.
"He's a guy that we've missed so far in these last few games," Dumoulin said about Letang, who leads Penguins defensemen with 12 points (four goals, eight assists) in 15 games. "He can come right in and not miss a step. We've seen it before. It's good to have him back."