They both tested negative.
The DFB said in a statement that the players' own "culpability of refusing or missing a doping test cannot be proven".
The pair had said in their testimony that they were told they needed to appear for a test only after they had gone to the dressing room at the end of the match.
The DFB said it would file a complaint against the team's doping official, who, according to the DFB, had been told at halftime which players had been chosen for testing.
If found guilty, the club face a fine and possibly the deduction of points from the match.
The DFB said should "new, as yet unknown accusations against the players arise then the process against them will resume".
It said it had also suspended the doping control doctor and his assistant who were in charge of the match for breach of duty as they had failed to enforce the strict World Anti-Doping Agency (WADA) and DFB doping rules.
Anti-doping commission chief Rainer Koch said: "Such mistakes cannot be repeated. In the future the DFB will insist on strict adherence to anti-doping guidelines and any breach will be taken to the sports court."
Hoffenheim have taken the league by storm in their debut season, leading the Bundesliga for weeks. They are currently third, two points behind leaders Hertha Berlin.
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