The former Blancos star believes the prolific striker's suspensiion could play a key role, but warned that BVB should not be underestimated by Carlo Ancelotti's men
The Poland international netted all of Dortmund's four goals in their 4-1 win in the second leg of the semi-final of last year's edition of the competition, but will miss the first leg at the Bernabeu due to suspension after picking up a yellow card against Zenit St Petersburg on Wednesday.
"The fact that they will be without Lewandowski in the first leg could have a negative impact on their game," Butragueno told reporters.
"Hopefully we can take advantage of his absence at the Bernabeu.
"We played Dortmund four times last season and they were very strong. I know they're not doing so well in the league this season, but we're aware they're still going to be a very difficult team to beat.
"There were stronger teams out there, but nobody wanted to be paired with Bayern. Our goal is to qualify for the semi-finals and we will see what happens."
The first leg at the Bernabeu is scheduled to take place on April 2.