The center was a game-time decision after he did not practice Saturday and missed a 5-1 loss to the New York Rangers because of an illness Friday.
"'Geno' still isn't feeling well," Penguins coach Mike Sullivan said Saturday. "We'll monitor how he feels throughout the course of the day. I would anticipate him being a game-time decision tomorrow based on how he feels."
Malkin participated in the morning skate Friday prior to the game at Madison Square Garden. Sullivan said he found out at lunch that Malkin wasn't feeling well and while on his way to the arena learned he would not be available.
He was on a three-game point streak (four points; three goals, one assist) after not scoring a point in six straight.
"It's not ideal, but I think we've been in situations like that before," Penguins captain Sidney Crosby said. "We understand that something like that can happen. Everybody prepares for what they need to do and that's no excuse for the way we played."
The Penguins fell behind 3-0 in the first 4:16 of the first period. They were outshot 33-21.
Defenseman Mark Friedman replaced Malkin and played 5:08 in 10 shifts as a forward.
Malkin scored 28 points (13 goals, 15 assists) in 29 games this season. He missed games on Feb. 8 and 10 while in NHL COVID-19 protocol.
Pittsburgh has a point in 10 in 12 games (8-2-2) entering the game Sunday (5 p.m. ET; ATTSN-PT, BSDETX, ESPN+, NHL LIVE). The Penguins are 19-8-5 since Malkin debuted Jan. 11 after having knee surgery June 4. They started 20-9-5 without him.
Rickard Rakell was going to play on a line with Malkin for the first time Friday. He was acquired in a trade with the Anaheim Ducks on Monday and played on the third line Tuesday in a 4-3 shootout loss to the Buffalo Sabres.
"We're trying to figure out what combinations give us the best chance to win, and that's what we'll continue to do," Sullivan said. "'Rak's' obviously a real good player. He's a goal-scorer, has the ability to finish. I think he adds a lot of speed to our lineup. We're just trying to figure out how to create combinations out there that give us the balance we need through our lineup but also put players in position to be successful. We'll see where it goes, but we're just trying to explore some options here to figure out where people fit."
Goalie Casey DeSmith was the back up to Tristan Jarry against the Red Wings after playing 4:19 in relief of Jarry on Friday. DeSmith left in the second period with a head injury but was at practice Saturday.
"Casey checked out fine," Sullivan said.
NHL.com independent correspondent Wes Crosby contributed to this report
