Zub is being evaluated after sustaining a lower-body injury, Bruce Garrioch of Postmedia reports Wednesday.
Zub had five goals, 25 points, 139 hits and 122 blocks in 69 games with Ottawa in 2023-24. Travis Hamonic isn't a certainty to serve on the Senators' top six when their campaign starts Oct. 10 versus Florida, but if Zub ends up missing that contest, then Hamonic will likely dress.