Arsene Wenger has confirmed Arsenal have activated a one-year extension clause in Per Meresacker's contract.
Mertesacker, 32, has not played this season having suffered a serious knee injury during the club's pre-season campaign. His current deal was due to expire this summer but speaking at a press conference on Thursday ahead of their Premier League clash with Burnley, Wenger revealed the centre-half's future has now been resolved.
When asked about talks over a new deal for the Germany international, Wenger told reporters: "Per has an option that we have taken, so there was no negotiation. It's just an option we have taken."
The defender is also edging closer to his return from injury with Wenger expecting him to return to full first-team training within two weeks.
"He's back in training, not with the squad but he's two weeks away now. It is important we have all our experienced players back, we are going into the moment of truth now, January to May, and you ideally want all our players with experience back in the squad."
Mertesacker was a first-team regular alongside Laurent Koscielny in the Arsenal backline last season, making 36 appearances.
He is the latest player to have his future at the Emirates resolved with Olivier Giroud, Laurent Koscielny and Francis Coquelin all signing new deals earlier this month. Wenger was unable to offer any update on contract negotiations with Alexis Sanchez or Mesut Ozil, whose deals expire in the summer of 2018.
Ozil has indicated he will sign a new deal with the Gunners, but only with the assurance that Wenger will stay on as manager. Sanchez meanwhile has insisted he is "really happy and comfortable" at the Emirates stadium, amid reports suggesting both players are demanding wages of £290,000-a-week, equal to that of the world's most expensive player Paul Pogba of Manchester United.