Stop for a second. This doesn't thin out the roster. Moving out Kulich's potential for Robertson's actual, is not thinning out the roster.
I think it's absurd to call a trade of Kulich Östlund and 9 for Robertson "thinning out the roster"
Also injuries as an excuse not to do something is loser talk. You have no control over that and worrying about it means you're making moves based on fear.