Jurgen Klopp's Dortmund side have a lengthy list of absentees coming into their Group D encounter in Belgium.
Marco Reus (ankle), Jakub Blaszczykowski (muscle problem), Nuri Sahin (knee), Oliver Kirch (thigh) and Henrikh Mkhitaryan (foot) are all unavailable for the visitors, while Ilkay Gundogan's long-term back injury renders him highly unlikely to feature and Sebastian Kehl's foot complaint means he is also a doubt.
Despite their opponent's injury woes, Hasi sounded a warning about the threat posed by the 2013 runners-up, even in light of Dortmund's 2-1 defeat to fierce rivals Schalke in the Bundesliga at the weekend.
"It's never the right time to deal with such clubs," he said. "But it's true that the club is in a somewhat difficult period and has a lot of injuries.
"But I do not let myself be blinded by his defeat at Schalke. We are not a club in the Bundesliga, but the Pro League.
"For Dortmund, it's easier to play against Anderlecht as against Schalke. I expect that their game will be better on Wednesday, but ours will be as well."
Anderlecht have a fitness concern over Anthony Vanden Borre, who is yet to feature this season after fracturing his fibula in the World Cup with Belgium, while fellow defender Fabrice N'Sakala is out with a knee problem.
Hasi's men earned a 1-1 draw against Galatasaray in Turkey on matchday one and have made a strong start to the defence of their Pro League title, unbeaten after nine matches and with a four-point lead over second-placed Gent.
Dortmund, by contrast, have struggled for consistency in the German top flight, losing three of their opening six games to languish 12th in the early table, already seven points adrift of Bayern Munich.
Following Saturday's loss at Schalke, defender Mats Hummels declared it was time for the team to show their fighting spirit.
"We are not where we want to be just now," he said.
"We have simply endured eight bad days and the comeback trail starts on Wednesday in Anderlecht."
Klopp, meanwhile, echoed the sentiments of Hummels as Dortmund look to build on their 2-0 home victory over Arsenal in their opening group fixture.
"The team has quality, a strong character and is mentally strong," he said. "We will be back."
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