The 32-year-old arrives at Elland Road with one Spanish international cap to his name along with three Champions League winners’ medals.
Casilla will not feature against Stoke City in the Championship tomorrow, Bielsa having already announced that Bailey Peacock-Farrell will start to allow the Spaniard to acclimatise to English football after playing his entire career in La Liga with Espanyol and the Bernabeu club.
“We needed an alternative for the goalkeeper position,” said Bielsa, Jamal Blackman’s broken leg having left the Argentinian with just one fit senior goalkeeper since mid-November.
“I do not have to make any comment on Casilla because his career speaks for itself.
“The fact that he has chosen to play in Leeds is a success for the institution. Victor Orta (United’s director of football) is responsible for the arrival of Kiko Casilla and the analysis of the compatibility of his skills with our play has been done by Marcus Abad, the goalkeeping coach.
“The fact that the goalkeeper comes from Real Madrid, the owner of this club should be proud being able to attract that kind of player.”
Casilla has joined Leeds on a free transfer, the Championship club having agreed a deal that will see them take over the remaining 18 months of his Real Madrid contract.
He has signed a four-and-a-half-year deal at Elland Road. The 32-year-old, who won his solitary cap for Spain in 2014, started his career with Real and then rejoined the club in 2015 after eight seasons with Espanyol.
Casilla, part of Zinedine Zidane’s squad in each of the past three seasons when the Spanish club lifted the Champions League, has made 43 appearances for Real since returning to the capital for £5m.
“I think he is the complete player,” said Bielsa. “He is a good player when he has to block shots from the opponent, he is a player with personality.
“He is good with his feet and with balls in the air. We can’t say that one of these aspects is his strong point, but I do not see any weak points.
“He has had his first training session (yesterday) so what I can say is that he will not play against Stoke even if he is fit. We will see his evolution in the next few days and take a point of view.”