Kuba relaxed after Lewandowski departure
The Poland international left for Dortmund's arch rivals and German champions Bayern Munich in July after spending four prolific seasons at Signal Iduna Park.
He followed Mario Gotze in leaving for the Allianz Arena and Dortmund boss Jurgen Klopp now has a major goalscoring void to fill.
Striking trio Adrian Ramos, Ciro Immobile and Ji Dong-won have all arrived this close-season, and Blaszczykowski feels those new recruits have what it takes to cover his compatriot's absence.
"It's normal in this business that some top players leave but Borussia still lives on because new good players arrive," he told Kicker.
"Everyone decides for themselves what is right for him. Nuri Sahin, Shinji Kagawa, Mario Gotze and Robert Lewandowski now have left Dortmund but Borussia but still lives on, because every year good new players have come.
"We will be helping Adrian Ramos, Ciro Immobile, Matthias Ginter and Ji so that they can be integrated quickly and we find ourselves as a team."
Blaszczykowski has not featured for Dortmund since tearing an anterior cruciate ligament in January, but is on the road to recovery at the club's close-season training camp in Bad Ragaz.
"I feel good. Although I'm still not completely pain free, I realise that it will get better by the day in training," he added.
"I am pleased with how [the recovery] has developed and I am glad that it will not take a long time."