The League One side are understood to have accepted a bid of £1.2million plus add-ons from Lech Poznan for the 26-year-old.
Helik arrived at Barnsley in the summer of 2020 from Polish outfit Cracovia Krakow, and has since made 89 appearances for the Yorkshire club across all competitions.
During the 2020/21 campaign, the Pole was named Barnsley's Player of the Season as the club finished fifth in the Championship and competed in the play-offs.
Last year, the Reds were relegated to League One which subsequently led to the departure of key players including Callum Brittain, Cauley Woodrow and Carlton Morris.
Helik has also been linked with a move away from Oakwell as he looks to put himself in contention for a place in November's World Cup.
The defender has made seven international appearances for Poland since his 2021 debut - a 3-3 draw with Hungary in a World Cup qualifying fixture.
According to Polish news outlet Interia Sport, the total sum of the transfer - including bonuses - could be as high as £1.67million.
As things stand, the biggest transfer in the history of Polish club football was made by Legia Warszawa who signed Bartosz Slisz for £1.66 million during the 2019/20 campaign.
With that in mind, Helik could become the most expensive player ever in the Polish Ekstraklasa.