The same reason you would trade any player, to make the team better.
Do people really think that Tuch is our path to the playoffs, let alone a SC? Jesus. We’re so in awe of merely seeing an actual NHL player on the ice in a Sabres uniform, that we want to abandon what this year is supposed to be about? (develop the young’ns, yet still end up with high draft picks) Dont get me wrong, i like his smile, too, but if trading him can make the team better in the future, they have to do it.