Bayer Leverkusen were unable to latch onto their good form from the first half of the season during their winter training camp, while FC Schalke 04's performances under new coach Jens Keller have so far also left plenty to be desired.
Fortuna Düsseldorf are another team who have failed to convince since returning from the festive break, losing the Wintercup which they hosted and duly joining Eintracht Frankfurt on our list of sides needing to up their game swiftly heading into the second half of the campaign....
In contrast to their performances in the league so far this term, the Werkself have failed to make such a positive impression during the winter break with just one win in three friendly matches. Nevertheless, Stefan Kießling saw the positives after a win against Dutch side NEC Nijmegen: "You could see that we were tired, but we showed a good attitude and totally deserved to win. That was a great end to some hard weeks of training."
Leverkusen come out of the blocks in 2013 having made two changes to their playing staff. Young Polish striker Arkadiusz Milik has arrived from Gornik Zabrze while Renato Augusto headed home to Brazil with Corinthians. Defenders Michal Kadlec and Daniel Schwaab are still sidelined by injury.
Top fact: All twelve of Leverkusen's goals which came from a striker so far this season bear one name: Stefan Kießling. He is the league's top scorer.
Leverkusen's first opponents of 2013 are Eintracht Frankfurt, the best of the league's three promoted clubs so far. Yet they have struggled to shine this winter. In friendlies with Borussia Mönchengladbach and Al Jazira Club of the UAE, Eintracht shipped a total of eight goals. "Of course we can't be happy that we've conceded so many goals," said head coach Armin Veh. "Simply by playing the attacking football we play, you're bound to concede more. The problem is we're not scoring that many either."
The Eagles have signed Marco Russ back from VfL Wolfsburg, while Vadim Demidov has left the club for Spain.
Top fact:Alex Meier is the Bundesliga's second-highest goalscorer and, with 11 goals, he has already posted a personal season's best with only half of the campaign gone.
A new beginning was the order of the day in Gelsenkirchen when Jens Keller was appointed as coach at the end of the first half of the season. However, their first test, against Bayern Munich, hardly gave reason for optimism. "We're confident that we'll be able to get back to our best come the second half of the season," said defender Christian Fuchs. "However, we do know that we've got to improve if we want to achieve our goals." The Royal Blues need to bounce back from that 5-0 drubbing when they take on Hannover 96 on Friday night. Unfortunately for them, Klaas-Jan Huntelaar is suspended and Kyriakos Papadopoulos, Marco Höger and Ibrahim Afellay are all out injured.
Edu has returned to the Royal Blues from Greuther Fürth while Lewis Holtby has announced he will be leaving in the summer to join Tottenham Hotspur.
Top fact: Schalke 04 had the second-strongest defence in the Bundesliga in terms of efficiency with 61 per cent of all tackles won in the first half of the campaign.
Fortuna Düsseldorf got off on the wrong foot this winter with a 3-0 friendly defeat to FSV Mainz 05. Though they made up for that with a 4-1 victory over Belgian side RAEC Mons, it was at the Wintercup that the hosts' greatest deficiencies were exposed in two defeats. "We really struggled against Dortmund, which was down to the quality of our opponents, but also my team's lack of aggression," said coach Norbert Meier. "Teams of Dortmund's pedigree punish you for that."
Of the two new signings this winter, Mathis Bolly has made a better impression than Japanese forward Genki Omae in friendly matches, indicating that he could well feature in Meier's side to face FC Augsburg at the weekend.
Top fact: No other team have been as clinical as Fortuna in front of goal this term. Whenever they were presented with a big chance, 67 per cent of the time the ball ended up in the back of the net. They only missed four sitters - fewer than any other side.