Per Mertesacker will definitely miss the start of the new season for Arsenal, with Arsene Wenger confirming the centre-back will be out of action for a "few months". With several of the key first-teamers set to miss the beginning of the season as well, owing to their exertions in Euro 2016, and in Alexis Sanchez's case â€“ Copa America Centenario â€“ the Mertesacker injury leaves Arsenal seriously short at the back, in terms of experience.
Gabriel was ruled out of Arsenal's US tour owing to tonsillitis, which means the club will play the MLS All-Star game and the friendly against Chivas de Guadalajara with three young central defenders in the squad â€“ Calum Chambers, Krystian Bielik and new signing Rob Holding.
More worryingly, though, it means Wenger, who confirmed the Mertesacker blow in a press conference in the US, will have to choose from the three youngsters and Gabriel for the opening English Premier League match against Liverpool on Aug. 14, with Laurent Koscielny, whose France side made it to the Euro 2016 final, not expected to be match fit by that time.
While Wenger is someone who has no qualms over playing young players, the fact that this season is expected to be the most competitive yet, with every single of the 20 teams on their way to strengthening their squads considerably, the Frenchman will know he needs a more experienced centre-back signing.
Kalidou Koulibaly was linked with a move earlier this summer, but Arsenal reportedly backed out after Napoli demanded an excessive fee. Jeison Murillo of Inter Milan is also reportedly under consideration, while Daniele Rugani, 21, is another defender from the Serie A that Arsenal have monitored, even if the Juventus centre-back will, again, fall in the young-and-not-experienced-enough category.
Arsenal have also been tipped to make a bid for Valencia defender Shkodran Mustafi, with the Premier League club, according to Italian journalist Emanuele Giullianeli, making contact with the player's agent over a possible move.
Mustafi makes sense, because at 24, he still has his best years ahead of him, but, having played in two major tournaments for Germany, he also has the experience. The fact that Mustafi, a former Everton player, can also play as a right-back, if needed, further enhances the chances of Wenger making a bid.
With Mertesacker ruled out for a few months, reports suggest it could be as long as five, Wenger needs to make a move quickly in order to ensure Arsenal do not start the new season on the back foot.