Brilliant coach that he is, there have long been question marks against Bielsa over the course of a league season. Essentially his methods involve such intensity and levels of energy that questions have been raised as to whether they are ideal for doing well in cup competitions/tournaments but unsustainable over a whole domestic league season.
While his Athletic Bilbao played some sensational football to reach the Europa League final their league form was more mediocre with a final position of 10th. The following season they finished 12th.
When in charge at Marseille they started 2014-15 in sensational style, being winter champions. However they fell away badly in the second half of the season finishing 4th.
Hi last major position at Lille was a disaster as the team struggled in the relegation zone and he was sacked by Christmas.
If his players tired in the second half of a season in France then there has to be a question mark as to whether he could sustain success over 46 games in the Championship where physicality is a major factor.