Other Premier League and Championship clubs use data analysis in a similar way, according to Simon Austin, editor of the Training Ground Guru website.

And Austin believes it could be a matter of time before a data expert takes on the role of manager.

"What is clear is that more and more managers are buying into this data analysis," Austin told Press Association Sport.

"You could see Pep Guardiola coding on his laptop whilst on a train journey in the Manchester City documentary and managers like Lee Johnson and Gary Rowett can clip and code video, too.

"We are also starting to see analysts get promoted to assistant coaching roles. It happened at Leicester. The next step will be when an analyst becomes a manager."

Bielsa has been condemned by some managers and former players after admitting he had sent staff to spy on every team Leeds have played this season.

Bielsa admitted a man removed by police from the perimeter of Derby's training ground had been sent by him.

Leeds have formally apologised to Derby and both the Football Association and English Football League have launched investigations.

"What was really different about Bielsa's press conference is that he was disclosing what they do – nearly every club does tactical analysis now, they just don't talk about it and it's hard to know what they are actually doing," Austin said.

"Using software called Sportscode, you can clip up bits of video and turn it into data.

"As of this season, coaches can now see these clips and replays of action on handheld devices during the games.

"So the dugout is seeing which part of the pitch most shots are coming from, where the ball is spending the most time, where it is being won and lost and so on.

"So there is a huge amount of match analysis being done. And then you've got all the tactical work they do during the week in training, which is based on what their opponents have been doing."

Austin said Bielsa's data analysis was unusual because of how far back he goes, while the Leeds boss himself said most of the information he gathered was to appease his anxiety and was unnecessary.

"The other issue to think about is how much of this information any player can take on board," Austin added.

"Pep Guardiola, for example, is known for only giving a few key messages before each training session or game..

"But the type of tactical analysis Bielsa talked about is being done by all the big clubs.

"Liverpool, for example, have a research team with four people in it, one of them has a PhD from Harvard, another a PhD from Cambridge. And Arsenal bought a company called StatDNA that is meant to be on a different level of sophistication."

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