Marcelo Bielsa concedes Samuel Saiz is going through 'ups and downs' at Leeds United this season

Saiz had been ever-present under the Argentine in the league ahead of last Saturday's 1-1 draw with Nottingham Forest but Bielsa opted to play Adam Forshaw in place of the Spaniard for the visit of Aitor Karanka's men.

The 27-year-old though stepped off the bench and had a major impact as he played a key role in Kemar Roofe's controversial leveller which earned the Whites a point.

Bielsa, who was speaking ahead of tomorrow's visit to the DW stadium, admitted that like any footballer Saiz is going through "ups and downs" but remained staunch in his belief that he is one of his best assets at Elland Road.

"Samu Saiz is a great player," Bielsa said.

"He is the player who can create the lack of balance that our team needs. He’s the only player in our group who can create this lack of balance.

"Taking into account what he did so far this season and what he did last year because I saw the games he played last year too. I’m not making an opinion about last year, it’s just I saw how he played last year and I can talk about him.

"He’s the player who can create the best lack of balance in the offensive sector.

"And the most important pass that ended with the goal we scored was made by Samu Saiz.

"His last pass is the most aggressive one we have and after having praised him like that, you're going to ask me why he doesn’t play. He’s not playing because he’s going through ups and downs and things like this happen in a competition with 46 games.

"Sometimes we have to explain why Samu Saiz is not the starter, but other times we have to explain why Forshaw is not starting.

"That means a team needs a lot more than just 11 players."