The Gunners will bank an initial £2million after agreeing the deal with a £12m option to buy available to Steve Cooper’s side in the summer.
Mikel Arteta has deemed the left-back surplus to requirements after he spent last season on loan at Marseille.
Tavares will leave having played just 28 times since signing from Benfica in 2021 for £6.8m.
Arsenal are keen to offload a number of players who have not made Arteta’s matchday squads of late, including Rob Holding, Albert Sambi Lokonga, Cedric Soares and Nicolas Pepe.
Chelsea target Emile Smith Rowe, however, is not for sale as a key part of Arsenal’s plans.
Nottingham Forest, meanwhile, will also sign Corinthians midfielder Murillo for £13m and are in talks to sign former Chelsea striker Michy Batshuayi from Fenerbahce.