According to ESPNChicago.com's Jesse Rogers, Eager had been ruled out of Thursday's game against the Detroit Red Wings with an upper-body issue.
The 25-year-old Eager has been held scoreless in two games with the Blackhawks this season. Eager, who is a native of Ottawa, Ontario, posted career highs in goals (11) points (15) and games played (74) last season. Eager also lead the team and ranked 13th in the NHL with 161 penalty minutes. Eager has notched 501 penalty minutes and 36 points in 197 regular-season games spanning parts of six seasons with the Philadelphia Flyers (2005-2008) and the Hawks (2008-09).
The Hawks will host the Colorado Avalanche in their home opener at the United Center on Saturday at 7:30 p.m.