Injury to Jan Vertonghen represents Tottenham's biggest test yet

This morning, Tottenham Hotspur confirmed that Jan Vertonghen has sustained "damage" to his medial collateral ligament (MCL). The team, as is their custom, offered no further word on the severity of the injury, whether it would require surgery, or the timetable for Vertonghen's return.

Our medical staff will continue to monitor his progress during his rehabilitation to determine when he will be ready to return to training.

— Tottenham Hotspur (@SpursOfficial) January 26, 2016

What happens now represents the biggest test yet for Tottenham Hotspur and manager Mauricio Pochettino. Replacing Vertonghen is a tall order and managing the squad for however long the Belgian is out of the lineup will be a similarly difficult task.

It has been well documented that Toby Alderweireld and Vertonghen had, up until 75 minutes into the Crystal Palace match, played every minute of Premier League football together. The two Belgian internationals have formed a very cohesive partnership which many pin on their experience playing together at Ajax and for Belgium (even though they rarely play center back together from their country). The two have combined to help give Spurs the best defense in the league, conceding less than a goal per game. Now, however, Spurs will be down to only one Belgian in defense.

The task of replacing Vertonghen seems to fall on the barrel-shaped body of Kevin Wimmer. The Austrian defender joined Spurs this summer, but has found playing time to be sparse in his first six months with the club. He's played so little, in fact, that Schalke were allegedly in "advanced talks" to bring Wimmer back to the Bundesliga. Now, Wimmer finds himself thrust into the heart of defense for a Tottenham team that is making a push for the title.

Wimmer is certainly more than capable of filling in for Vertonghen. He possess slightly different attributes from Jan, but Wimmer is a left-footed center back who appears to be confident on the ball. The most noticeable differences between Wimmer and Vertonghen are pace and positioning. Vertonghen, while he has played more conservatively this season, is not a stranger to a marauding attacking run. Wimmer, on the other hand, prefers to stay deep not get forward much. This is likely down to his lack of pace. I don't mean to imply that Wimmer is Fazio-esque when it comes to movement, but he's somewhere between that and Vertonghen.

The key may be how quickly Tottenham's new defensive partnership adjust to each other. Wimmer has played a little over three matches with Toby Alderweireld this season (Qarabag, Monaco, Leicester, and part of the Crystal Palace match). Spurs are unbeaten in all of those matches, for whatever that is worth. In those matches, Alderweireld has, as he has for much of the season, played more advanced, even pushing forward to recycle possession when Spurs are keeping the opponent penned into the attacking third. Wimmer, meanwhile, stayed back with defensive midfielder Eric Dier. This doesn't represent much of a change for Spurs, but all the matches in which Wimmer has featured, Spurs have been on the front foot throughout. It will be interesting to see how Wimmer copes with more pressure and what positions he takes up relative to Alderweireld.

Now, Spurs face the prospect of playing with this partnership for at least the next month, probably two depending upon the severity of Vertonghen's injury. That run features matches against Manchester City and Arsenal, two of Tottenham's biggest rivals at the top of the table. Not to mention a handful of potential FA Cup and Europa League matches. That crammed schedule in particular represents a test for Pochettino.

Pochettino has been loathe to rotate his squad this year, instead relying on a core group of "his guys." Wimmer has mostly not been one of those guys. Now, he's been drafted into action leaving Tottenham with little center back depth behind him. Pochettino now faces the prospect of having to turn to Federico Fazio in case of emergency. Of course, Eric Dier could fill in in a pinch, but that would weaken the midfield. Similarly, Ben Davies has played center back for Wales, but two left-footers in center defense doesn't seem like the kind of balance Spurs want. There are additional options, of course. Milos Veljkovic is still a person who exists, after all, as does Cameron Carter-Vickers.

Regardless of how Pochettino handles the squad, the lack of depth could present the problem should another injury arise. Fortunately, Alderweireld has avoided accumulating many yellow cards this season, so a suspension seems unlikely. Pochettino's biggest task will be ensuring that his defensive partnership remains fit and that his tactics adjust to fit the new center back pairing.