What to watch out for on Matchday 23

Dortmund look to continue latest upswing

What was the worst part about Borussia Dortmund's German Cup game against Sportfreunde Lotte getting postponed? BVB were in a stretch of solid form after two straight 3-0 victories against Wolfsburg and Freiburg, something they could have used to punch their ticket for the semifinals. They will have to hope they can draw from their recent success when they host Leverkusen on Saturday.

Leverkusen have been a good match for Dortmund since Roger Schmidt took the reigns before the 2014-15 season. Each team has two wins and a draw in their last five matches. Though Leverkusen got off to their worst league start in 10 years this season, they still managed to get a 2-0 victory in October, when these two teams last met.

Dortmund won't want to drop points again, especially since they climbed back into the top three last week for the first time since November. They also have an important Champions League second leg match against Benfica to prepare for, leaving BVB coach Thomas Tuchel with a lot to handle as he tries to keep his team on an upswing.

Can Cologne trouble the defending champs again?

Cologne are one of the six teams to have taken points off of league leaders Bayern Munich this season. More impressively, the 1-1 result they registered in October occurred at the Allianz Arena in Munich, and it was the first time that the Billy Goats have collected points there in six years.

Now Cologne get a crack at the defending Bundesliga champions on their own turf. However, they have lost two of their last three games and have fallen to seventh place in the table after a strong start. Getting points against Bayern would go a long way to reversing their form and to keeping their hopes of European competition next season alive.

Europa League prelude

Schalke and Borussia Mönchengladbach better get used to each other because, after getting paired together in the Europa League, they will play each other three times within the space of 13 days. The first bout will be in the Bundesliga, where both are trying to claw their way back in mid-table after rough starts to the season.

Hosts Gladbach are the team in better league form, having lost just once since the recent appointment of Dieter Hecking. Schalke meanwhile are coming off a demoralizing 3-0 defeat to Bayern in the German Cup and have scored one goal or fewer in nine of their last 10 league games. The Foals are the ones with the better odds this weekend, but if Schalke can't get it right this time around, they will have two more opportunities to better their opponents.

Jonker's debut and Malli's return

Many eyes will be on newly appointed Wolfsburg coach Andries Jonker as he begins his difficult task of stabilizing the club. The Wolves have lost four of their last five league games going into Saturday's contest against Mainz, a run of results that cost Valerien Ismael his job. Their recent signings have done nothing to change the status quo, but hope may spring anew for the relegation-threatened club under Jonker, who was an assistant at the club during the 2012-13 season.

One of Wolfsburg's new signings, Yunus Malli, will be making his return to his former home for the first time. Malli spent five-and-a-half seasons at Mainz before he completed a move to Wolfsburg in January. Ironically, Mainz have performed slightly better without Malli, collecting eight points in six games.

Frings faces former club

Following the end of his playing career in 2013, Torsten Frings came up through the coaching ranks with Werder Bremen as Viktor Skripnik's assistant, both with the reserves and, upon Skripnik's appointment in 2014, the first team. But he was relieved of his duties when Skripnik was sacked early in the season.

Frings' sacking freed him up to take his first head coaching job with Darmstadt, and he now faces his former team in a vital relegation battle - Darmstadt are entrenched at the bottom of the table while Bremen are trying to avoid the drop zone. But Frings, speaking in a press conference in Darmstadt on Thursday, said he had "absolutely no problem with anyone at Werder."

"We always had a good relationship. (Bremen sporting director Frank Baumann) made this decision from his professional position. That hasn't changed anything in our personal relationship," said Frings.