bundesliga.com is on hand to bring you all the pre-match news from both camps...
After crashing out of Europe a week ago, Lucien Favre's Gladbach will hope to maintain their push for a top-four finish with a fifth win in seven league games. Mainz, meanwhile, will be looking to maintain their improvement in form under coach Martin Schmidt as they look to distance themselves from the drop zone.
Schmidt has the luxury of being able to pick from a largely fit group of players, with only Tudor Nedelev, Christoph Moritz and Pierre Bengtsson set to miss out. Junior Diaz (pictured) could come in to replace Bengtsson, while Christian Clemens, who scored in the club's last home game, should retain his place in attack.
Similarly, Favre's job has been made easier in that the Foals are only missing Spanish defender Alvaro Dominguez. Andre Hahn started in the DFB Cup in midweek but could drop out for Ibrahima Traore, while Raffael is in line for a recall to the first XI.
With leading scorer Shinji Okazaki out of form and without a goal in his last eight matches, Yunus Malli has taken on much of Mainz's attacking responsibility. A precociously gifted midfielder, he has four goals in 2015 so far and will be keen to prove what he can do against the club whose youth teams he played for between 2007 and 2011.
Patrick Herrmann was a team-mate of Malli's when they were in the Foals youth set-up, but the 24-year-old will leave no room for sentiment this weekend. Herrmann also has four goals to his name this year, including two winners on Matchdays 18 and 19 that have been key to Borussia maintaining their momentum in the European race.
Schmidt: "He [Favre| is an outstanding personality, and that he's established himself as a Swiss coach in Germany makes him a role model. If we give it our all, play our own game and have a good day as well, we can take something from the game."
Favre: "They'll be very tough opponents. They played very well to beat Frankfurt 3-1 and were very unlucky to lose at Hoffenheim; they could have been two or three up after an hour. I haven't met my colleague [Schmidt] yet but I look forward to getting to know him on Saturday."
Mainz have won one and lost one under the new management, but their performance at TSG 1899 Hoffenheim last week suggested they are slowly regaining their confidence. Gladbach, for their part, have lost just once this year at FC Schalke 04 and come into the game on the back of a solid 2-0 cup win at Kickers Offenbach.
Gladbach boast a marginally better record in this fixture having won seven and drawn five of the sides' 17 Bundesliga meetings to date. A Jonas Hofmann penalty helped the 05ers to a 1-1 draw in this fixture back on Matchday 7.
Mainz: Karius - Brosinski, Bungert, Bell, Diaz - Geis, Baumgartlinger - de Blasis, Malli, Clemens - Okazaki
Gladbach: Sommer - Korb, Stranzl, Jantschke, Wendt - Herrmann, Xhaka, Kramer, Traore - Raffael, Kruse