Hitzfeld, who has managed both clubs, speculated that the amount of Bayern's players involved in Germany's World Cup-winning squad could make them slow-starters this year.
Injuries to Bastian Schweinsteiger, Thiago Alcantara and Javi Martinez also threaten to hamper the defending champions, according to the 65-year-old.
"I think it is even more difficult for Bayern Munich than for Borussia Dortmund," Hitzfeld said.
"Bayern had more players in Brazil and at the end, seven world champions. Bayern also have injury problems… Schweinsteiger, Martinez, Rafinha, Thiago.
"Therefore, one can assume that it remains very exciting until the winter. We [neutrals] must hope that Dortmund has a good start and can put pressure on Bayern."
Hitzfeld feels Dortmund are Bayern's only realistic challenger though, writing off the chances of the likes of Bayer Leverkusen and Schalke.
"I don't see any team which can be dangerous for either Bayern or Dortmund," he added.
"As for the Champions League places, Schalke, Bayer Leverkusen, Wolfsburg and Borussia Monchengladbach [will compete]…Leverkusen has signed good players: [Hakan] Calhanoglu, [Josip] Drmic, Wendell. Leverkusen had already a good team last season.
"Schalke will be seen because they have problems again and again. It is a very busy club and there is a crisis quickly. Wolfsburg has built a good team and has also become better.
"Monchengladbach has tactically developed and can set the tone offensively. It'll be a duel between Bayern and Dortmund [though]."
Hitzfeld also added that he felt stepping away from his post in charge of Switzerland after the World Cup was the correct call.
Switzerland were knocked out in the last 16 by eventual finalists Argentina, on penalties.
"I feel very good and it was the right decision, to finish [as head coach of Switzerland] after the World Cup," he added.
"I am 65 years old and I can stop in full possession of my powers. I made the decision for myself and have not been dismissed."