Fabbrini's contract was due to expire this summer.BCFC
The 28-year-old has a deal in place to sign for Romania side FC Botosani as a free agent.
Fabbrini has spent the past 18 months loaned out, first to Italian team Spezia in January 2017 then to Spaniards Oviedo in August 2017.
Fabbrini suffered a serious cruciate knee ligament injury at Oviedo in his first week of training and eventually came back to make his debut in February.
Garry Monk told Fabbrini that he was not in his plans for this season and he has been seeking a club to get fixed up with.
Fabbrini's contract was due to expire this summer.
Signed from Watford, he joined Blues on loan in March 2015 before being secured on a permanent transfer 10 months later.
Fabbrini's last appearance for Blues was in the FA Cup against Newcastle United shortly before Gianfranco Zola loaned him out to Spezia.
In total Fabbrini played 28 game for Blues and failed to score.
FC Botosani play in Romania's top tier and finished eighth last season.
The Club would like to thank Diego for his service and wish him all the best for the future.