That's what I initially thought too but I rewatched it and interpreted it differently. At 4:25 in the video he clearly says 10 of the guys will be new "meaning they're either rookies, or they've played maybe under 10 games last year". I'm thinking he either misspoke or doesn't know what he's talking about, especially after bringing in Troy Mann who has been preaching the importance of development in Belleville and that vets will have to work hard to earn their spots.
I wasn't masochistic enough to sit through the video, but here's how the team tried to backtrack those comments, via Ian Mendes:
"The organization did try and clear up one misconception from Monday’s video, involving Melnyk’s suggestion that 10 new players would be on the roster for opening night of this season.
Melnyk — they say — was actually comparing this year’s opening-night roster to last year’s, which featured the likes of Kyle Turris, Mike Hoffman, Derick Brassard, Dion Phaneuf, Nate Thompson, Alex Burrows, Johnny Oduya, Andrew Hammond and others.
The club says that comparing those two rosters side-by-side is how Melnyk came up with the number of 10 fresh faces for the 2018-19 campaign."
I think what probably happened is Melnyk tried to sell young, exciting players, and exaggerated by a factor of 3 or 4 how many rookies will actually make the team, leaving the organization in clean up mode.