Bayern have not topped the table under coach Juergen Klinsmann this season and with 10 matches left they are in second place, four points behind leaders Hertha Berlin.
During Ribery's two-week absence with a shinbone problem, Bayern qualified for the Champion's League quarter-finals and scored back-to-back league wins but his return coincides with news Miroslav Klose will be out for at least six weeks.
Forward Klose's absence with an ankle injury follows that of Italian Luca Toni, who has been sidelined for almost four weeks with a heel injury, leaving Lucas Podolski as their only fit striker.
"We believe that Franck can play again (on Saturday)," Bayern manager Uli Hoeness told Bavarian television this week.
Ribery, instrumental in Bayern's league and German Cup double last season, has been complaining about a shaky defence this season that stifles his offensive play by forcing him further back to carry the ball.
Against bottom-placed Karlsruhe though, the Frenchman will play his attacking midfield role with Podolski either as a lone centre forward or partnered with Toni, if the Italian is fit.
EFFECTIVE BERLIN
Leaders Hertha Berlin, on 49 points, travel to VfB Stuttgart in what could prove a tricky encounter for the visitors, chasing their first championship since 1931.
Stuttgart, who had not lost in the league since late November, suffered a stinging 4-0 defeat against Werder Bremen last week that could prove to be an awakening for Markus Babbel's side.
Hertha have been hugely efficient this season, often needing only half a chance to win matches, and with striker Andriy Voronin on a goal-scoring run and Marko Pantelic fit to partner him up front, they seem up for the challenge.
"Few would have thought at the beginning of the season Hertha could play like that," Stuttgart's Babbel said on Wednesday. "Their play is impressively effective."
Surprise-package VfL Wolfsburg could also stay level on points with Bayern if they extend their six-game winning streak that has let them shoot up the table since the winter break.
Their hosts Arminia Bielefeld have not lost in four matches but Wolfsburg's in-form strike partnership of Grafite and Edin Dzeko, who have scored a combined 30 league goals, is a formidable challenge to their opponents' defence.
Grafite, who took his tally to 17 with a hat-trick last week, needs only a goal to go joint top of the scorers table with Hoffenheim's injured Vedad Ibisevic, who is out for the rest of the season.
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