The Polish wide-man is also contributing around €300,000 of his own money to assist the club, who find themselves in the midst of a financial predicament.
Wisla, who have the joint-second most Polish league titles in history (level with Legia Warsaw on 13) saw a proposed takeover by a wealthy Cambodian business collapse at the turn of the year.
The corporation had failed to settle the club's debts by a deadline of December 28, causing the deal to be invalidated and leaving Wisla in a state of financial limbo.
BIG NEWS from this morning: @jarokrolewski the passionate IT entrepreneur, KUBA BŁASZCZYKOWSKI and a third yet publicly unnamed person will contribute 1.3mln PLN (300K€) of their OWN money, so that the outstanding players' wages can be paid. This is a lifeline for Wisla. Respect— WISŁA News 🇬🇧🇵🇱 (@WCracowNews) January 12, 2019
However, Blaszczykowski, who represented the club between 2005 and 2007 before joining Borussia Dortmund for a reported fee of €3m, has, along with two other investors, given the club a lifeline out of his own pocket.
Additionally, he has agreed to join their ranks without a wage in an admirable show of loyalty.
The money provided will help the club pay outstanding wages and give the hierarchy time to negotiate a possible takeover with any interested parties.
Wisla sit eighth in the Polish top-flight, some 13 points off the top, but will hope the return of a player with considerable Bundesliga experience will restore them to something approaching their former glory.
All respect to our Kuba, who is on the verge of joining his boyhood club Wisla Krakow without pay and has assisted them financially to help revive the Polish side 💛👏🏼 pic.twitter.com/IkRdWobzFy— Borussia Dortmund (@BlackYellow) January 12, 2019
Dortmund have lauded their former player's generosity, hailing his loyalty - a trait the club experienced first-hand following nine years of faithful service, with Blaszczykowski often playing out of position wherever needed to help the team.