The village team, who are setting the pace with a squad of relatively unknown professionals, will be toppled from the summit if champions Bayern win at Hamburg SV on Friday.
Hoffenheim, who lead Bayern on goal difference, host Energie Cottbus on Saturday but will be without Vedad Ibisevic, the league's top scorer with 18 goals, for the rest of the season with a ruptured cruciate ligament.
Obasi also misses out against Cottbus due to a thigh injury while midfielder Carlos Eduardo is suspended for two matches after a punch-up with Hamburg's Ivica Olic in a friendly.
The 5-1 demolition of VfB Stuttgart in the German Cup on Tuesday sent an ominous warning to Bayern's Bundesliga title rivals.
"This was a clear signal to our competitors that we are ready," said coach Juergen Klinsmann after Bayern's emphatic away win took them into the quarter-finals.
"We are fully armed for the next four months and if we continue playing like that it will be extremely hard to beat us."
Klinsmann's side travel to Hamburg with no major injury concerns and in the knowledge their last league defeat was back in September.
The defence will also be breathing easier knowing dangerous Hamburg striker Olic, who scored a hat-trick in Tuesday's 3-1 German Cup win over 1860 Munich, will not be playing.
