The injury is not related to the concussion that had sidelined the league's MVP for four games, the coach said.
"That is not a concern," Bylsma said, according to the Pittsburgh Post-Gazette.
Malkin appeared to hurt his shoulder in the final minutes of regulation in a 5-4 overtime victory against Toronto on Saturday night when he collided with Maple Leafs forward James van Riemsdyk. Malkin returned to play one more shift but did not take the ice in overtime.
Malkin has five goals and 24 points in 21 games.
Sidney Crosby, who had five assists in the Pens' rout of the Isles on Sunday, says Malkin will be missed.
"It's not a guy we're going to replace," Crosby said, according to the newspaper. "Everyone knows that. I think everyone probably puts a little more pressure on themselves, but we don't want to change too much with the way that we play and our identity."
Information from The Associated Press was used in this report.