Laurent Koscielny Stretchered off with Achilles Injury vs. Atletico Madrid

Arsenal defender Laurent Koscielny's season looks to be over after he was stretchered off in the second leg of his side's UEFA Europa League semi-final clash against Atletico Madrid with a reported torn Achilles. 

The France international left the field early on at the Wanda Metropolitano on Thursday evening, and James Cross of the Mirror later confirmed the worst fears:

James Olley of the London Evening Standard initially sent concerns it could well have been a serious injury:

Calum Chambers came on as his replacement after recently making an impression in Sunday's 2-1 defeat to Manchester United, and the Englishman could now be a vital player for the season run-in.

Get French Football News echoed Olley's concern and went so far as to question whether Koscielny will be fit to feature at the 2018 FIFA World Cup, which is set to get underway in just over a month's time on June 14:

Koscielny was reduced to tears and slapped the turf as he clutched at his Achilles tendon, perhaps in the knowledge the severity of his injury will likely sideline him for more than just a few weeks.

Particularly worrying was the fact the 32-year-old went down with no opponents close to him, often a calling card of the most damaging injuries.

Arsenal's domestic campaign is all but over with three games remaining and no chance of a top-four finish in the Premier League, but losing their most senior defensive force at this stage is a big blow nonetheless.

Arsenal host Burnley on Sunday and will be level on points with the Clarets should they fall at the Emirates Stadium. They follow that with back-to-back trips to Leicester City and Huddersfield Town, respectively, with Koscielny now out of contention for that 10-day series of fixtures.

Shkodran Mustafi has had a patchy season but will now need to taken on a leader's role in central defence, while Nacho Monreal's status as senior man in the Arsenal back line will have a big role to play.