Borussia Dortmund is currently six points behind Leipzig and that is quite a lot so Dortmund will face quite a lot of difficulty in catching up, especially as the two teams above them can be said to be performing quite consistently compared to them so there is a big chance that we will see Dortmund only playing in the European leagues except for Leipzig and Stuttgart in the middle of the season experienced problems in maintaining their performance and Dortmund managed to make the improvements needed because their front line and their defense line were quite bad this season, of the top six teams in the standings they conceded the most.
After the New Year holiday, Dortmund will face three weak teams, they should be able to get 9 points to continue to maintain their chances of returning to the top four and securing a Champions League ticket.
Bundesliga top second standings automatically will be for Bayern Leverkusen and Bayern Munich, third and fourth standings seems will be place for VfB Stuttgart and RB Leipzig with both teams left one point only. Have problem for Dortmund can't return with top performance and left 6 points behind Leipzig on the fourth position standings. Dortmund performance in this season not promising yet and out from top fourth standings much problem for them how to get Champion League ticket next although their performance in Champion League most impressive get qualify to next round.
Dortmund have several easily matches after Bundesliga resume on middle January, if can take three points will not close for raising Champion League spot standings but depend on top fourth teams on impressive perform or not.
I really doubt Dortmund's consistency this season and also their strength is not that strong compared to last season, especially as Leipzig, Leverkusen and Bayern Munich have more strength than them so it is possible that Dortmund will not be able to finish above them.
For this season, I am sure that only Bayern and Leverkusen will compete fiercely in the fight for the Bundeliga title until the end of the season.