Sead Kolasinac has agreed to join Bundesliga side Schalke on loan for the remainder of the season, Arsenal have announced.
The Bosnia defender will head back to the club where he joined the youth set-up and went on to become a first-team regular before moving to the Gunners during June 2017.
Earlier on Thursday, Arsenal manager Mikel Arteta confirmed the club's priority for the January transfer window was to trim down the size of the current squad.
Kolasinac's last appearance for the Gunners was in the 4-1 Carabao Cup defeat by Manchester City on December 22.
During November, the 27-year-old had spent a period of self-isolation after the Bosnia and Herzegovina Football confirmed the defender has tested positive for Covid-19 while away on international duty.
Kolasinac's loan move is set to begin on January 4, with the full-back having made 113 appearances for Arsenal, helping the team reach the 2019 Europa League final against Chelsea.
Arsenal technical director Edu said on the club website: "Sead needs to be playing regularly, so we have decided together that a move back to Germany with Schalke will benefit him at this moment.
"We will be keeping in close contact with Sead, and wish him huge success for the remainder of the season with Schalke."