Dortmund's misfortune forces Klopp down new avenues – but could give Arsenal a headache

Visits to the doctor continue for Borussia Dortmund. The injury outbreak still isn't under control. Die Schwarzgelben once again have a list of notable absentees against Arsenal in the Champions League.

Marco Reus and Jakub Blaszczykowski are both sidelined for a month. Nuri Sahin possibly two. Ilkay Gundogan is nearing a comeback but not ready, while Mats Hummels and Oliver Kirch haven’t yet reached full fitness.

But the German side have been here before. Last season was hardly easy, yet astonishingly they managed to top their Champions League group after beating Marseille in a nail-biting Group F finale.

While this won't be Dortmund's strongest XI, the team has overcome obstacles at this level in the past. If the remaining able bodies can carry this team until the return of Reus & Co., Klopp's men could go far.

They'll face fierce opposition in Arsenal; eager to avoid finishing second and a last 16 death sentence, but also carrying significant injuries in defence. The two sides will meet for the third time in four years.

Arsene Wenger's team are entering intimidating territory, but will be confident after winning at the Westfalenstadion last year. The addition of Alexis Sanchez and Jack Wilshere’s recent form further cement their morale. Battling Galatasaray in a hostile environment will also serve as a huge test for Dortmund, meanwhile, and they would be foolish to let their guards down against Anderlecht.

Meet the new boys

But Jurgen Klopp has added depth and variety at his disposal in newcomers Ciro Immobile, Adrian Ramos, Matthias Ginter and the return of Shinji Kagawa from Manchester United.

Immobile was Serie A's top scorer last season and is determined to impress, but the Italian is still adjusting to Dortmund's style and high tempo. His link-up play in attack also needs work and he often appears to want to make an immediate impact, to the detriment of the team.

On the plus side, the Azzurri international adds directness and physicality, though he lacks the inventiveness, hold-up play and creativity of Robert Lewandowski.

Still, he's strong on the counter and gives Klopp's side more verticality, something that's become more prominent over the seasons since Mario Gotze's exit. To avoid one-dimensional build-up, the return of Kagawa and Reus should provide enough balance with their skills to operate effectively in tight spaces.

Meanwhile Adrian Ramos offers another choice up front and has scored twice in the last three games. Ramos’ best game was probably against Freiburg on Saturday, when he combined smoothly with Henrikh Mkhitaryan, Kevin Grosskreutz and Kagawa in attack. Korean Ji Dong-won has yet to start for the black and yellows, and was left out of their Champions League squad. 

As for Ginter, his inexperience showed against Leverkusen. He's a versatile and promising player, but still a liability. Overall, the back four has more depth than ever, and Sokratis' form has stood out this season.

Neven Subotic has also recovered, finally giving Klopp options once Hummels returns. Subotic and Sokratis, though, are still a work in progress. They're individually strong, yet when playing together lack positional awareness of one another.

Shinji let loose

But it was the return of the 'lost son' Kagawa that generated the most media hype. When Reus re-injured his ankle, it was a major blow to the club, pushing Kagawa to the forefront a lot sooner than expected.

"We can't wait a few weeks," said Klopp. "I can't say to Shinji: ‘Go sit in the stands. First sniff the atmosphere a bit.’ He is needed."

Although he hasn’t played that many games over the past two seasons, he’s adapted faster than anticipated. No wonder the Japanese international had goosebumps on his debut, after scoring and providing an assist on his comeback. With injuries piling up, this was exactly the sort of performance Dortmund needed.

Klopp's side have the most depth in defensive midfield, but it's also that position which has been hit the hardest with Gundogan, Sven Bender (finally back but only fielded as a sub so far), Sahin and Kirch all injured.

That leaves Milos Jojic and 34-year old Sebastian Kehl to cover most of the ground. The duo don't complement each other, and this remains Dortmund's weak spot. On the plus side, Gundogan is on the road to recovery. He played a full 35 minutes than the planned 15 last week against the club's Under-23s.

SEE ALSO Cult hero Kagawa doesn't disappoint on his Dortmund homecoming

Blessing in disguise

Together, the injuries and new players have tactically diversified the black and yellows. Klopp has deviated from his usual 4-2-3-1 and shown no fear in setting up his players in 4-1-3-2 and 4-1-4-1 formations. Most notably, Dortmund used an unconventional 4-4-2 against Real Madrid last season to much success.  

The two-striker system remains an option. Recently Klopp tried it against both Leverkusen in the league and Bayern in the Supercup, but results were mixed. It proved effective against Bayern's three-man back-line, yet they struggled to get on the scoresheet in their Bundesliga opener and subsequently lost. It's forced Klopp to use a lone striker up front, rotating Pierre-Emerick Aubameyang, Ramos and Immobile.

The newly acquired versatility is important and gives the team more options and a plan B, something Klopp often received criticism for lacking previously. Even though it evolved more out of necessity than choice, it's worked in their favour.

Hummels also remains an important part of the team. His ability to get involved in attack and set-pieces, not to mention his strength of playing the ball out from the back, is an edge over any opponent.

Reports suggest he'll start training again on Wednesday, but has been ruled out against Arsenal. As have Gundogan, Reus, Sahin, Kuba and Kirch. Once these players come back, regain fitness and the newcomers make a smooth transition, this team could finally find glory on the biggest of stages in European football.

If, of course, the injury bug doesn’t wipe out the entire squad first.