Sledgehammer Games is developing the next title in the Call of Duty: Modern Warfare series, according to one of the studio's employees.

Senior VFX artist Rob Valdivia states that he's "developing photo real visual effects for the next Call of Duty - Modern Warfare release" on his LinkedIn profile, having moved there from PlayStation All-Stars dev SuperBot in April 2013.

Valdivia's profile has since been removed but is still visible in Google Cache.

His comments suggest that Sledgehammer could be gearing up to release Call of Duty: Modern Warfare 4 next year. The studio previously co-developed Modern Warfare 3 with series creator Infinity Ward.

Despite earlier speculation, Infinity Ward confirmed back in May that its latest game Call of Duty: Ghosts, due for release this November, is set in a "completely different universe" to Modern Warfare, featuring an all-new cast and story.

Activision gave a "no comment" when contacted about Valdivia's profile earlier today.