The Mexican was a regular on the scoresheet for Roger Schmidt's side last season but has found goals harder to come by this term, failing to find the back of the net since the start of October.
The 27-year-old's goalless 708 minutes have led to Schmidt taking him out of the starting line-up in recent matches, Hernandez beginning the last two Bundesliga games on the bench.
Voller has now given his support to the former Manchester United frontman to find the back of the net soon, predicting he will end his goal drought before the winter break.
"We still have a few games until the winter break. I am convinced he will score another goal," he said.
Voller went on to say that Leverkusen "need his goals" with Schmidt's men in 10th in the Bundesliga after last weekend's defeat to Bayern Munich.