After a less than impressive season at the Emirates, club skipper Thomas Vermaelan's future is in doubt.
It is understood that Arsene Wenger is pondering selling the Belgian. after Koscielny and Mertesacker cemented their centre-back partnership during the Gunners collosial run-in at the end of the season.
Arsenal boss, Wenger is looking to shake up his squad, as he looks to create a team capable of winning Arsenal's first competition in 8 years.
Reports claim that the North Londoners are willing to sell the centre-back at a £5m loss on the £10m they paid Ajax in 2009.
In another twist to the tale, Manchester United have emerged as front runners to sign Vermaelen- who would follow in Robin van Persie's footsteps if he were to go to Old Trafford.
Neither clubs nor the player are yet to comment.