The Argentine ace is third in the pecking order at the Emirates.
Petr Cech is firmly established as Arsene Wenger's first-choice stopper.
Meanwhile, David Ospina is regularly deployed as Cech's understudy.
Martinez's chances of becoming No.1 at Arsenal look slim.
But according to The Sun, Valencia are willing to make him top dog in Spain.
Despite his status as a backup shout stopper, Matinez's possible exit could give Wenger a headache.
Ospina is being chased by cash rich Turkish outfit Fenerbahce.
If both Ospina and Martinez depart, the Frenchman could be left scratching around for two goalkeepers.
Arsenal still have Poland international Wojciech Szczesny on their books.
However, he's spent the last two seasons on loan at Roma.
His performances haven't gone unnoticed in Serie A and champions Juventus are keen.
Wenger is a long-term admirer of Stoke stopper Jack Butland, The Sun claim.
But the England international is highly rated by Mark Hughes and it would cost big money to secure his services.
