Yeah he's played a 3rd/4th liner role in Liiga with limited ice time and games (no powerplay responsibilities either apart from like one game). I think his stats are a bit unflattering compared to his effect as well, since he does a lot of good things when he's on ice and creates tons of chances there too. TPS just doesn't have too good quality finishing in their bottom lines and he has been a bit unlucky as well with his own chances.Slafkovsky is interesting case and he has been one of the breakthrough players of this tournament, if not the breakthrough player.
He has only 1+3 in his 21 Liiga games, but I think that is due him having limited role. His ice time is about 13 minutes per game.
You could see his quality by watching his games there for sure, but he's taken it to a better level in these olympics too.