Marcel Schmelzer and Kevin Grosskreutz are definitely out while Mario Gotze and Marco Reus are doubtful after withdrawing from the Germany squad for the midweek win in France.
"The way things stand, Marcel and Kevin are unavailable," said Klopp, who may also be without first-choice goalkeeper Roman Weidenfeller.
"But there won't be any excuses or alibis, just a team who has trained a bit less than usual."
A 3-2 victory at Bayer Leverkusen last weekend moved the defending champions up to second place in the table but they are still 12 points behind runaway leaders Bayern Munich.
A title challenge looks beyond their reach with second place, and direct qualification for next season's Champions League, a more realistic target.
Three points against Hamburg on Saturday would help them towards that objective but having seen a club-record 31-game unbeaten run ended by the northern Germany side in the reverse fixture, it will not be an easy task.
Klopp is optimistic his men can avenge that defeat, though.
He said: "We said when we were down in the dumps after being beaten by them earlier this season that we would win the points back at home.
"So let's just see what we can magic up."
Dortmund's injury woes were in stark contrast to the clean bill of health delivered by Hamburg coach Thorsten Fink at his pre-match press conference.
"All of those who were on international duty have returned without injury, which is very important," he said.
Those who stayed in Germany, like Rafael van der Vaart and Artjoms Rudnevs, are fully fit too.
Only Milan Badelj is missing due to suspension, but even his absence is not a cause of concern for Fink, whose job was on the line before the victory at home to Dortmund back in September lifted the gloom.
"Maybe the break will do Milan some good," he said. "He's not been looking so fresh psychologically of late."