Shkodran Mustafi has left Arsenal to join Schalke on a free transfer, talkSPORT understands.
The Germany defender has agreed to cancel the last six months of his Gunners contract to secure a move back to his homeland.
Mustafi, who signed for Arsenal in a £35million deal from Valencia in 2016, has made just nine appearances under Mikel Arteta this season.
The 28-year-old was behind Gabriel, David Luiz, Rob Holding in the pecking order at the Emirates.
Now, Mustafi reunites with his former Arsenal teammate Sead Kolasinac, who returned to Schalke on loan last month.
Along with the departures of Mustafi and Kolasinac, Sokratis Papastathopoulos mutually agreed to leave the Gunners before signing for Olympiakos in the same transfer window.
Elsewhere, West Brom have reached an agreement to sign Arsenal midfielder Ainsley Maitland-Niles on loan.
Leicester and Southampton were also in for the England international, who can operate in midfield or defence.
But West Brom have won the race for his signature with Maitland-Niles set to undergo a medical in London this evening.
Maitland-Niles has started just five Premier League games this term.
The 23-year-old will be looking to aid the Baggies’ survival hopes with Sam Allardyce’s side nine points from safety.