Die Schwarzgelben desperately need to kick-start their domestic campaign and will have been lifted by their midweek Champions League win over Napoli.
Borussia Dortmund will hope its impressive record against Mainz can secure the team's first win in three Bundesliga matches Saturday.
The sides meet at the Coface Arena and it is the hosts who are in better domestic form, having won three of their last four top-flight games, with Shinji Okazaki finding the net on four occasions in that time. However, Mainz has not beaten Saturday's opponents in its last six attempts, as Jurgen Klopp returns to a club where he played and coached.
Dortmund has stalled somewhat in the Bundesliga recently, though, losing 2-1 at Wolfsburg prior to the international break before going down 3-0 at home to champion Bayern Munich last time out.
Despite injuries to the likes of Marcel Schmelzer, Mats Hummels and Neven Subotic, Dortmund kept its hopes of Champions League qualification alive Tuesday with a stirring 3-1 win over Napoli. Sven Bender sustained a broken nose in that match but was able to finish the game, although Klopp is keen to leave any decisions on selection until as late as possible.
"We will look carefully to know who can cope with the burden [of playing twice in five days]," he said. "We will deal with the issue of rotation and look for who is fit."
Klopp signed Manuel Friedrich in an attempt to bolster his depleted defense and shared his pleasure at how the 34-year-old has fitted in at Signal Iduna Park.
"Manny embodies all that makes up our game and what we have shown in recent years," he said. "He has an exceptional character."
Dortmund has dropped points in half of its Bundesliga matches on the road this season, while Mainz has not lost at home in its last three.
Mainz coach Thomas Tuchel has also been handed a boost with the news that Zdenek Pospech is fit despite being taken off in the win over Werder Bremen, while Christian Wetklo is available for a return after serving his suspension.