Arsenal have met Thomas Partey's release clause of £45m.
The Atletico Madrid midfielder is now flying to London to complete a switch to the Emirates before the transfer window shuts.
The Gunners have been trying to free up wage space to sign Partey.
Matteo Guendouzi departed for Hertha BSC on deadline day.
Lucas Torreira is expected to join Atletico Madrid and Sead Kolasinac is in talks to sign with Bayer Leverkusen.
