Eichel is considered day-to-day.
Goaltender Linus Ullmark will also miss Friday's practice as he is quarantining due to an immigration issue. He's expected to return to the ice in the coming days.
Buffalo's captain has been vocal about his desire to reach the post-season in 2020-21, and while this is certainly a rocky start, there is plenty of room for optimism after the franchise's busy off-season, which saw new GM Kevyn Adams add Taylor Hall, Cody Eakin and Eric Staal.
The Sabres, who opened their training camp on Thursday, were one of seven teams not to make the Stanley Cup Qualifiers last season. They have not made the playoffs since 2010-11.