Alioski/Dallas roles explained

Roles of Alioski and Dallas have been interesting recently, swapping positions - can you explain that to us?

Bielsa
"They both played the majority of the game on the left-hand side. In this sector on the left-hand side there were three heights. The level where James Rodriguez moved, the height or level where Iwobi moved and the height or level of the pitch where Godfrey arrived. There were combinations of movement to attack and defend.

The more advanced ones are Harrison and Raphinha and Alioki who was in front of Dallas and behind the winger. And Dallas who was the furthest one back. The three of them had obligations to defend and attack and with the possibility to interchange functions. At the end of the game Dallas and Alioski started to change sides but this was a small proportion of the game"

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