The striker revealed that the departures of the Brazilian centre-back and Germany international had hurt the team and that it may take time to recover from their absence
The Foals ensured a place in the Champions League qualifying round with a fourth-placed finish in the Bundesliga last season, but lost the first leg of their tie with Dinamo Kiev 3-1.
Whilst discussing Wednesday's second leg with Uefa.com, the 28-year-old striker admitted that the departures of key players had been partly responsible for their first-leg defeat to the Ukrainians and added that the club would need time to recover.
"They'd played a few more competitive games, including against Feyenoord in the last round, and we lost some important players over the summer – Dante, Roman [Neustadter] and Marco [Reus]," Hanke said.
"To compensate for those losses is very difficult. We can do it, we just need time, but that is what we don't have so we have to make sure that we try everything in attack and score three goals there.
"They say that in football anything is possible, so I just believe in that – that we can still make it."