The Germany international has scored only seven Serie A goals since joining La Viola in July 2013, a situation exacerbated by two separate injuries that resulted in lengthy spells on the sidelines.
But Super Lig club Besiktas have now paid Fiorentina 3.5 million euros to give the 30-year-old an opportunity to revive his career in Turkey.
A statement published on bjk.com.tr on Thursday confirmed the former Bayern Munich player had arrived on a loan deal that could become permanent should Besiktas so desire.
Gomez arrived in Florence under a weight of expectation – and costing an estimated 20 million euros – after scoring 113 competitive goals in just four seasons with Bayern.
He has also represented Germany 60 times, scoring 25 goals. Gomez last appeared for Die Mannschaft in September 2014.