"He's a player with personality and character and he still has the margin to improve," Leeds' head coach said.

"But what he has shown in the season so far qualifies as a good season.

"Not only because he is young, even if he was 30 years old he would still be graded very well."

Leeds have lost four of their last six league games, but still aim to finish their first season back in the Premier League for 16 years in the top half of the table.

Monday's opponents West Ham have been one of the top flight's surprise packages and their top-four challenge has been noted by Bielsa.

He explained why he thinks the Hammers have been so successful under David Moyes this season.

"A secret or something special I don't observe," said the Argentinian, who picked out Declan Rice and Tomas Soucek as two players who have been key to the Londoners' progress.

"They've been able to maintain a stable partnership in midfield. They are two players who are very important."

Soucek was on target in West Ham's 2-1 win at Elland Road in early December, while Moyes' side have lost only to Chelsea, Liverpool and Manchester City in the league since.

"For each of the attacking positions, they have two players," Bielsa added. "Especially with the two wingers and offensive midfielder.

"The four full-backs they possess are important players. Apart from that, they have resolved the absence of (Arthur) Masuaku.

"Their two goalkeepers have shone and the centre-backs, not only have they been sure at the back, they have also contributed goals in attack.

"They have a very good set-piece taker (Aaron Cresswell) with his left foot and the manager has been able to obtain some very good minutes of football with that team."

Leeds forward Rodrigo (groin) and winger Ian Poveda (ankle) could return to contention after injury, but midfield pair Kalvin Phillips (calf) and Jamie Shackleton (groin) are unlikely to feature.