What makes Marcelo Bielsa a great manager is his ability to improve his players.

The likes of Stuart Dallas, Luke Ayling and Kalvin Phillips were all mid-table Championship players before El Loco arrived, but now they’re already looking like bona fide Premier League stars.

Bielsa has been able to improve almost every player he has worked with at Leeds, transforming the squad from a team that finished 13th in the Championship to champions of the second division, all while keeping a very similar core of the squad.

However, there is one player that has gone backwards under his tutelage.

Unfortunately, we’re talking about Barry Douglas.

The Scot arrived at Elland Road with one hell of a reputation, having assisted 14 and scored five in Wolves’ incredible promotion season, but since then he’s not come close to those types of numbers.

He’s had just five assists in two seasons since joining Leeds, while he’s still waiting on his first goal for the club.

The most frustrating thing about Douglas’ regression is that we know how good he can be, and if he reproduced his Wolves form he would undoubtedly be a Premier League calibre left-back. For one reason or another however, that hasn’t happened.

It’s rare for Bielsa to fail when it comes to bringing out the best in a player, but with Douglas he’s simply not been able to find the key to unlock his potential. Now the defender is set to head out on loan with his contract expiring in 2021, we may never see his best at Leeds.

Perhaps his incredible season at Wolves was more a testament to Nuno Espirito Santo’s managerial ability than his time at Leeds being a knock on Bielsa’s, but one thing is for sure, he has regressed since joining the Whites.