Talented attacking midfielder Abdi completed his switch to Wednesday in July 2016.
The Swiss international began his career at FC Zurich before moving to France to join Le Mans in October 2009.
Upon becoming a free agent in summer 2010, Abdi signed with Serie A side Udinese.
He spent two successful seasons in Italy and scored one goal in the Europa League against Celtic in Glasgow before joining Watford, initially on loan, ahead of the 2012/13 campaign.
Abdi excelled in the Championship and was a hit from the start at Vicarage Road, scoring 12 goals in 43 appearances during his maiden season in Hertfordshire.
Watford fell at the final hurdle that season, losing to Crystal Palace in the play-off final, but Abdi helped the club achieve their Premier League ambition in 2014/15.
He featured 33 times for the Hornets as Watford went up automatically, only narrowly missing out as league champions on the final day when a late Atdhe Nuhiu goal salvaged a point for Wednesday at Vicarage Road to give Bournemouth the title.
During Watford’s first season back in the top flight, Abdi made 38 appearances and scored two goals in wins over Stoke and Aston Villa.