Dortmund have dropped a lot of points in their poor games and although the gap between the top 4 is not that big the amount of points they need to catch up on is not that big, but if Dortmund are not consistent then it is impossible to achieve that result. If they want to qualify for the Champions League then they have to recover from the poor form they have been having and in the next games they have to be much more consistent. I think it is difficult for Dortmund to catch up on the top 4 because they are in 10th place even though the gap between them and the fourth position is not that big.
Dortmund lost a lot of points because they kept Nuri Sahin as Dortmund coach for too long, maybe if Dortmund management was quick in making decisions, Dortmund would not be in the top 10 right now. Now under the new coach Niko Kovac Dortmund is starting to improve although not completely stable but Dortmund in the last two matches in the Bundesliga showed a good trend even they won their last two matches with a clean sheet record even though in the previous match in the Champions League they drew against LOSC but that was not too bad they still had a chance to win in the second leg.
So if you look at Dortmund's current development, I am optimistic that they can be consistent in the remaining Bundesliga matches to finish in the top four, especially since they are only 6 points behind the top four. Next week they will face Augsburg, this is their chance to win so they can continue to catch up because in terms of quality and looking at the statistics of both teams, Dortmund is better than Augsburg, plus this match will be played in front of their own supporters, of course this will be an extra strength to get three points. In addition, what makes me optimistic that Dortmund can finish in the top four is because they are one of the big teams in the Bundesliga, so their slump will recover soon.