Koscielny's injury makes revamping the back four at Arsenal even more imperative
Seeing Laurent Koscielny being carried off on a stretcher with his face in tears added more gloom to Arsenal's loss to Atletico Madrid on Thursday.
What was already a sad ending to Arsene Wenger's reign as Arsenal manager was made even more depressing by the fact that Koscielny is now set to miss the World Cup with a torn Achilles tendon.
But Arsenal have precious little time to feel sorry for themselves or the centre-back, who has been the lynchpin of Arsenal's defence since his arrival in 2010. His long-term injury now means the club must double their efforts to revamp their backline this summer.
Shoring up the Gunners' defensive frailties and adding at least two new pieces to the back four was already the No. 1 priority for whoever comes in to replace Wenger as manager. But that newcomer will now be without perhaps the one piece he thought he could rely on at the start of his reign.
Koscielny has been far from perfect this season as mistakes have crept into his game, but when fully fit, he is still Arsenal's best defender. However, if Wenger's preliminary diagnosis of a torn Achilles tendon is confirmed, he should be sidelined until well past his 33rd birthday in September. And who knows how well that troublesome Achilles -- which has been a chronic problem for him in recent years -- will hold up after his recovery.
It all means that Wenger's successor can no longer count on Koscielny to be a big part of his plans -- which leaves him with a severe shortage of experienced centre-backs. Per Mertesacker is retiring this summer, while Shkodran Mustafi's future has been the source of speculation after an inconsistent campaign.
But without Koscielny and Mertesacker, the 26-year-old Mustafi is the only centre-back in the Arsenal squad who is older than 23. The others are Calum Chambers (23), Rob Holding (22) and Konstantinos Mavropanos (20).
The good news is that Chambers looks to have come of age in Arsenal's last two games, following up an excellent performance at Old Trafford by being arguably his team's best player against Atletico after replacing Koscielny. Mavropanos, meanwhile, impressed mightily at Manchester United in his first game since joining January but it's still unclear whether he's ready to be a regular starter next season. Holding's development has stalled somewhat this season after falling behind Chambers in the pecking order, so while he remains a promising talent for the future, he's probably not the player Arsenal need in the present.
Wenger himself has said centre-backs don't start to reach their prime until 23, so it would be a major gamble to enter the next Premier League campaign relying on so much youth at the back. Especially if they don't have the luxury of playing alongside an experienced leader such as Koscielny. The France international has hardly been an on-field general like a John Terry or Vincent Kompany but at least he provides a sense of calm and stability to the players around him.
The same can't be said for Mustafi, meaning the need to find a veteran defender this summer is now greater than ever.
So far, though, the only centre-back Arsenal have been seriously linked with is Freiburg's Caglar Soyuncu, a 21-year-old Turkey international who no doubt is very talented but also must be seen as a work in progress.
It all makes West Brom's Jonny Evans suddenly seem like an even more appealing target, especially as he could be available for just £3 million if the Baggies get relegated. The 30-year-old Evans was heavily linked with a January move to the Gunners, even though Wenger has traditionally shied away from signing players that old.
Evans would not be the ideal solution, but Arsenal may be reluctant to spend the kind of money that one of Europe's top centre-backs would command -- especially after blowing £35m on Mustafi two summers ago.
The Northern Ireland international has plenty of appeal, though, as someone who learned his trade under Alex Ferguson at Man United and has played more than 200 Premier League games to date. He would give Arsenal a ready-made starter who would also help the talented crop of youngsters in Chambers, Mavropanos and Holding grow into the players the club are hoping they will become.
However, Evans might not be the type of signing that new recruitment head Sven Mislintat will go for, with the German seemingly intent on uncovering more unknown prospects. That's certainly the right approach in general for a club like Arsenal -- and what Mislintat was brought in for -- but Koscielny's injury has put them in a position where they have to find a finished product (or two) this summer.
Arsenal's defensive struggles have gone on for too long, and the new manager will largely be judged on how quickly he manages to sort them out. That will depend in part on how Arsenal go about replacing Koscielny.
Mattias is ESPN FC's Arsenal correspondent. Follow him on Twitter: @MattiasKaren.