The 57-year-old initially took charge of the Basques two years ago and led the club to both the finals of the Europa League and Copa del Rey in his maiden campaign, along with a sixth-placed finish in La Liga.
However, he was unable to repeat his successes of 2011-12 last term, having presided over a relegation battle for much of the season, and his contract will now not be renewed as a result.
"The board unanimously decided against renewing Marcelo Bielsa's contract because we believe that a change is in the best interests of Athletic," said president Josu Urrutia in a statement.
Remember dribble that made it once Marcelo-Messi
The 57-year-old initially took charge of the Basques two years ago and led the club to both the finals of the Europa League and Copa del Rey in his maiden campaign, along with a sixth-placed finish in La Liga.
However, he was unable to repeat his successes of 2011-12 last term, having presided over a relegation battle for much of the season, and his contract will now not be renewed as a result.
"The board unanimously decided against renewing Marcelo Bielsa's contract because we believe that a change is in the best interests of Athletic," said president Josu Urrutia in a statement.