The Penguins star center took a heavy hit from Toronto winger James van Riemsdyk late in the third period and didn't take another shift.
"Just an upper-body injury, kept him out the rest of the game," Bylsma said after a 5-4 win over Toronto.
"Don't have one; he'll certainly be re-evaluated," Bylsma said. "In the game it was more precautionary than anything at that point in time."
Malkin recently returned after missing four games with a concussion.