Valencia have reportedly turned down an €18m (£15m) offer from Arsenal for defender Shkodran Mustafi.
The Gunners are believed to be searching for a centre-back to provide cover for Per Mertesacker, who has been ruled out for the first "few months" of the season with a knee injury.
According to Plaza Deportiva, the North London outfit's opening bid has been knocked back as the Spanish club want a fee of between €25m and €30m (£21m and £25m).
The 24-year-old, who has earned 12 caps for the German national team, has been a Valencia player since his 2014 move from Sampdoria.
