German midfielder barely featured for the Gunners' first-team.
Lucas Perez joined Arsenal from La Liga side Deportivo La Coruna.
Arsene Wenger enquired after €10m-rated Paraguay international who has been compared to Angel di Maria.
Jack Wilshere will be allowed to leave Arsenal on loan on transfer deadline day.
The 27-year-old becomes the Gunners' fourth signing of the summer ahead of Shkodran Mustafi arrival.
Calum Chambers has made 59 appearances for Arsenal since joining in 2014.
The 24-year-old has not started a game this season and is braced to leave the Gunners on loan.
Walcott has already scored and registered an assist for Arsenal this season.
Ferdinand was allowed to leave Manchester United as a free agent in 2014.
Almiron made his debut for Paraguay at this summer's Copa America tournament.
Granit Xhaka is similar to Emmanuel Petit, insists Wenger.
Monreal was replaced by Kieran Gibbs in the second half against Watford.
Arsenal secured their first victory of the season beating Watford 3-1.
Griezmann is reported to have held talks with Gunners boss Arsene Wenger during Euro 2016.
Wenger says Arsenal are unlikely to make further additions after Mustafi and Perez signings.
Chelsea beat Burnley and Tottenham rescue draw against Liverpool on busy day of Premier League football.
Wenger will call on youth team stars during the course of the season.
Lucas and Mustafi are expected to have arrived in London for their medical with Arsenal.
Arsenal are still seeking their first win of the 2016/17 campaign.
German international centre-back is poised to complete his £35m move from Valencia shortly.
Holding joined the Gunners from Bolton Wanders for £2m.
Japanese international only arrived from Sanfrecce Hiroshima in July, but failed to get a work permit.