sooo I was still
thinking about this post and i think i got it.
Tsuki sees here Suga
looks in the direction of Kags and looks too, and I think it’s like the
first foreshadowing in this episode (as it was only in the anime and not in the manga).
Later we see more
about how Tsukki doesnt make that much effort as the others, and
actually wonders why they train harder, if they only get hurt later.
I think that from
what he knows from before, he sees it now with Kags and Hinata too, because
of their fight and how much more they’re trying to get better at volleyball and then get hurt… I think that the
moment Tsukki knows that Kags is hurt becuase of his fight with Hinata.
Also i think it’s more visible on Kageyama (like Hinata is hurt too, and they are working on it, but he takes it better, i think? Hinata communicates better with the rest of the team, etc..)
so my conclusion is: lets say that tsukki really cares/is worried for kags because he sees how hurt he is