The defenseman entered NHL COVID-19 protocol Jan. 27 and was removed Tuesday. He missed three games.
Defenseman Shea Theodore is not playing. He left a 5-4 win against Anaheim on Tuesday with an injury.
Pietrangelo led Golden Knights defensemen in average ice time at 25:37 and scored four points (one goal, three assists) in seven games. Theodore led their defensemen with 10 points (three goals, seven assists) in 10 games and averaged 21:40 of ice time.
"It's great timing," Vegas coach Peter DeBoer said of Pietrangelo's return. "I think to have both those guys out of the lineup is a big ask for our group, and that's essentially what we did in the third period -- part of the second and the third -- the other night.
"I just think the fact that he can slide into [Theodore's] spot 5-on-5, on the power play, just protects our young defensemen there a little bit so that we're not overwhelming them too early with some of the things we're asking them to do."
Marc-Andre Fleury was the Vegas starting goalie after Robin Lehner sustained an upper-body injury during the morning skate.
Forward Tomas Nosek also did not play. The NHL removed him from the game Tuesday and isolated him from his teammates upon notification he tested positive for COVID-19. He was unavailable under the NHL protocol.
"It was difficult," Golden Knights captain Mark Stone said. "Obviously, a weird situation. I don't think many guys found out until after the second period, and we took every precaution possible to get to where we are right now."
The Golden Knights have dealt with multiple COVID-19 disruptions this season, including playing without their NHL coaching staff in a 5-4 shootout loss to the St. Louis Blues on Jan. 26.
They had their facilities closed and three games postponed afterward. They have won three games in a row since returning to play Friday and are in first place in the Honda West Division with a record of 8-1-1.
"You know, we've kind of become numb to it," DeBoer said. "I think we're a year into this now, between pausing [last season March 12] and then the bubble [Stanley Cup Playoff] experience.
"I think really our group, I can only speak for our group, is almost expecting the next adversity to be around the corner, and when it's there, the shock of it isn't the same, and you just handle it in stride. It's another day in the COVID world we live in, and hopefully, you know, the end is in sight."
Stone called it a new normal.
"At the end of the day, you're getting to play NHL hockey games," the forward said. "This is what, I think, everyone here has worked their whole lives for, so we're not going to take it for granted. You come ready to play. You've got to be prepared no matter what the circumstances are."
