Mauro Zarate has ended his spell with West Ham by joining Fiorentina on a permanent contract.
The forward has not featured for West Ham since the 1-0 FA Cup third-round victory over Wolverhampton Wanderers on January 10 and has joined Fiorentina for a fee believed to be £1.6m.
"I would like to thank David Sullivan and David Gold for believing in me and for giving me the opportunity of playing at such a special club like West Ham," Zarate said via his official Twitter account.
"I would also like to thank my team-mates for the good times we shared and wish them the very best for the future, and especially I would like to thank from the bottom of my heart all the West Ham supporters for their unconditional support and affection, you are truly unique.
"Thank you all very much! COYI."
Zarate joined West Ham from Argentinian side Velez Sarsfield in the summer of 2014, but spent the second-half of the 2014-15 season on-loan at Queens Park Rangers after falling out of favour under then-manager Sam Allardyce.
He was reintegrated into the first-team squad at the beginning of the current campaign following the appointment of Slaven Bilic as Allardyce's successor and has featured in 21 matches, scoring five times.
West Ham co-owner David Sullivan confirmed to Sky Sports News HQ the club were hoping to sign a new forward in the next seven days and the departure of Zarate is likely to have freed up funds for them to continue their pursuit of a new frontman.
Sky sources understand the Hammers have made a bid to take Fenerbahce striker Emmanuel Emenike on loan for the remainder of the season.