The 31-year-old moves on from Oakwell after three seasons with the South Yorkshire outfit, arriving in 2000 from Premiership side Everton.
Ward captained The Tykes last season but suffered ankle problems in November and only made 30 appearances for the club.
New manager Gudjon Thordarson has decided to look at new faces and let Ward move on to pastures new for the upcoming season.
The former Stoke City boss has cast his eye over a number of trialists since taking the Barnsley hot-seat, with three more faces in pre-season training on Thursday.
Thordarson has brought in former Sheffield United central defender Kevin Murphy, former Walsall goalkeeper Gavin Ward and former Doncaster Rovers winger Andy Watson to run the rule over for the next few days.
Meanwhile, youngster Nathan Jarman has suffered a fracture in his hand during pre-season training.
The 16-year-old striker, however, will continue to train and wear a protective cast on his injured hand.
