Hien sat down in his own penalty area after a duel. The centre-back was then led off the field and substituted.
Sweden's goal scorer Anthony Elanga had not had time to talk to Hien when he met the media in the mixed zone.
"I haven't met him yet. He's an important player for us. But the ones who came in helped a lot, and you know what that means, we're 26 players so everyone has to be ready when they step on the pitch," Elanga said.
Goalkeeper Jacob Widell Zetterström:
I actually met him at halftime, and now after the game. Very sad, of course. It's something you never want to see. In our group we support each other in good and bad times. Even though it probably feels really tough for Isak, he knows we are here.
The national team's press officer Petra Thorén:
It was the back of the thigh. He will be examined. I haven't been told when, but I think it will be difficult for him to make it tonight (local time). I assume it will be tomorrow, but I haven't had time to talk to Jonas (Werner, the national team doctor). As soon as we know more, we will come out with information, she said.
The point against Japan was enough to take Sweden through to the round of 16.
