Hossa was scratched after he left during warmups ahead of Monday's Game 3, and the Blackhawks missed his offence in a 2-0 loss to the Bruins. The Blackhawks said Monday night that the Slovakian winger had an upper-body injury and was "day-to-day."
He was replaced by Ben Smith, 24, who made his first appearance in this year's Stanley Cup playoffs after suiting up for just one regular-season game in 13.
Hossa, 34, has seven goals and eight assists this post-season. He is tied for the team lead in points with Patrick Sharp and Patrick Kane.
The Bruins lead the best-of-seven championship series 2-1.