Midfielder Gundogan hit his head in their final group game last week and only trained partly with the team on Monday. Fullback Gosens and central defender Rudiger lasted the entire session but were feeling the effects of an infection.
"For all three we will have to see how it develops and we will decide tomorrow," Loew told a news conference. "We cannot say now. We have to wait. I do not know that yet tonight."
Loew, who will leave the job at the end of the tournament after 15 years at the helm and would be in charge of his final game if they lose, said a knockout stage game meant spectacular football could be sacrificed in favour of a result.
"In the group we came through (with world champions France and Euro holders Portugal as well as Hungary) there was no beauty prize to be won," Loew said.
"It was only about coming through this group and now we have an all-or-nothing game. So we can only say we have to go out and win it.
"You don't want to play a spectacular game and then stand there in the end with nothing to show for it. We want to win it but you still have to put in a good performance."
England have not defeated Germany in the knockout stage of a major tournament since the 1966 World Cup final, losing at the 1990 World Cup, Euro '96, and 2010 World Cup, the first two defeats coming after shoot-outs in the semi-finals.
England have also never won a knockout match over 90 minutes at the Euros. Four of their knockout stage games went to shootouts and England progressed only once -- against Spain at Wembley in 1996.
But for Loew that matters little.
"It is a completely different situation (from 1996) for example," he said. "England are a strong team with world-class players.
"All matches between Germany and England are talked about years later. It is a game that enthralls people. It is an all-or-nothing game and we must win it," he said.
The winner of Tuesday's game will face either Sweden or Ukraine in the quarter-finals on Saturday in Rome.