Highmore (upper body) was placed on waivers by Ottawa on Monday, Elliotte Friedman of Sportsnet reports.
In order to put Highmore on waivers, he would have needed to be medically cleared, meaning he should be ready to get back into the lineup. The 28-year-old center figures to start his season with AHL Belleville as he works his way back from injury but should be a strong candidate for a call-up later in the season.