The January transfer window is still three months away, but the Thorgan Hazard rumors, just like his goal-scoring form keep picking up pace. (Here's his goal against Barcelona from yesterday.)
But while everyone so far has claimed that Chelsea have a limited-time buy-back clause on our former player (set to expire at the end of the year), here comes Borussia Mönchengladbach director Max Eberl to confuse the situation a bit. Note that these are auto-translated quotes from German, so perhaps there's something quite literally lost in translation, but here it goes.
"There is no clause. There is also no deadline for anything."
"I don't want to comment on any elements of the contract [but] we also don't need to make any secrets about it: If we get a top player from Chelsea, then of course Chelsea also have the opportunity, in any form whatsoever, to think about them for themselves again — but they haven't actively done so!"
So, basically, there is no buy-back clause, but there could be some sort of unwritten agreement? Sounds a bit sketchy...
Meanwhile, there's also Andreas Christensen, who's situation is much more clear, but who's future is possibly just as muddled. The understanding is that Chelsea want him back in the summer, while Gladbach are willing to break their transfer record for him. Something's got to give, so it's hardly a surprise that Eberl describes the situation as "complicated". Again, these are rough translations of the quotes from Express, so if anyone speaks better German, feel free to pipe up in the comments.
"It is a complicated situation and we need to have this conversation with Chelsea. [...] We all know that the conversation won't go: "Can I have him?" Yes! "How much?" This much! "Okay, I'll pay. Goodbye."
"We have a very good relationship with Chelsea. This is going to take time. We will tackle the issue, unfortunately I can not promise that it will happen tomorrow or the day after. Our position is clear — we have to see when and how to implement it."
-Max Eberl; source: Express via Google Translate
The buy-back (or lack thereof) in Thorgan's case would make that situation far more speculative, but when it comes to Christensen, there's only one acceptable outcome for Chelsea. Bring him back when the loan ends at the end of the season. Period.