RB Leipzig sporting director Markus Krosche admits they're delighted with the impact of Patrik Shick.
The striker is on-loan at RBL from AS Roma.
Krosche said, "He has adapted perfectly here and this is also the perfect place for him.
"With our style of play he is in a situation where he can make the most of his strengths."
Piatek's deal doesn't include a set price for a permanent transfer.