"He's still being evaluated as to the extent of the hit and going into the boards hard," Bylsma told reporters after practice. "That's an ongoing process at this point in time."
Malkin, the Hart Trophy winner last season, was injured Friday night in a 3-1 victory against the Florida Panthers. Florida defenseman Erik Gudbranson checked Malkin early in the third period, and the Penguins center fell awkwardly into the end boards.
Rossi reported Malkin is experiencing concussion symptoms, including "severe headache and mild disorientation."
The Penguins play the Tampa Bay Lightning on Sunday in Pittsburgh.
"There's nothing to expect from this point," Bylsma said of Malkin. "He's getting evaluated. We're waiting to see how he feels and reacts. He went into the boards pretty darn hard. We're not expecting any timeline to the injury or anything."