Penguins coach Mike Sullivan did not provide an update but said the initial prognosis was positive.
"It's a funny way to score, but a goal is a goal," Sullivan said.
Crosby said he was hopeful Malkin would not miss extended time.
"It was one of those ones, I think got him in the right spot," Crosby said. "He looked like he was in a lot of pain. … I think it got him pretty good, but hopefully, nothing that's going to keep him out. If you are going to get hit, at least get a goal out of it."
Reinhart cut it to 3-2 with a one-timer off a pass from Carter Verhaeghe at 10:13, but Guentzel scored an empty-net goal with 1:18 remaining to make it 4-2.
"Five-on-5, I think we controlled a lot of the play," said Verhaeghe, who missed the previous game with an illness. "We still need to do a better job generating a little more, getting pucks to the net and getting some higher-quality looks."