After a strong start to the season that saw Jurgen Klopp's men claim nine wins in their opening 11 league games, Dortmund stuttered from November until the mid-season break.
A run of one victory in six Bundesliga matches, which included four defeats, meant Dortmund lost contact with Bayern at the top of the table at the end of 2013.
However, Kehl has not given up hope of catching the defending champions and is confident that Dortmund have the quality to challenge.
"Bayern plays this year in a different league," he told Bild. "But we will not raise the white flag (in surrender).
"There is always a point in a game where you can beat them.
"We have insane quality, but we must also be consistent to (ensure we at least) finish in second place."
Dortmund, who travel to Freiburg this weekend, have 11 games left in the Bundesliga campaign, with matches against Bayern, Bayer Leverkusen and Schalke still to come.
