Dortmund, who played second fiddle to treble-winning Bayern Munich last season after dominating in 2011 and 2012, lost Goetze to the Bavarians, who signed the Germany international in a reported 37 million euro deal.
Central defender Felipe Santana has also left to join Ruhr valley rivals Schalke 04.
"Our team is intact and despite the departures we are very solid," Kehl told Bild newspaper. "Our team will certainly not be worse than last year. I believe that we will be even better."
Despite having plenty of cash to spend following their run to the Champions League final and the revenue from the Goetze deal, Dortmund have so far only brought in central defender Sokratis Papastathopoulos to replace Santana.
Kehl, however, sounded confident the club would soon become more active in the transfer market.
"It is not easy at the moment because other clubs seem to be demanding horrendous transfer fees. But I am certain (club bosses) Juergen Klopp, Michael Zorc and Hans-Joachim Watzke will keep their promise and bring in the right reinforcements."
Kehl also said he expected highly coveted leading striker Robert Lewandowski to be playing for Dortmund next season.
"I am very happy about that. Robert, with his qualities, is extremely important for us."
The Pole, who refused to sign a contract extension to his deal that expires in 2014, was keen to move to Bayern but Dortmund insisted he would not be sold to their rivals this year.
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- Bayern Munich
- Felipe Santana