Saiz has largely been exceptional since arriving at Elland Road in the summer, often proving to be Leeds' most dangerous player and providing a number of goals and assists already.
It would have undoubtedly raised a few eyebrows when the teamsheet ahead of their game with the Tigers was announced and Saiz was absent from the matchday squad, with Pablo Hernandez replacing him in the Whites' starting lineup.
And after the game - which Leeds would win 1-0 thanks to Hernandez, who scored a brilliant chip after a Hull mistake - Christiansen confirmed that injury was the reason behind Saiz's absence, but insisted that he will be ready for the trip to Burton Albion on Boxing Day.
"He said he could play. I know this type of injury and I didn't want to risk him, and he will be in for the next game."
With Saiz an important part of Leeds' season to date, it would have undoubtedly given the squad a significant boost that they managed to win without a player who had almost become something of a talisman - often providing the quality in the games when Leeds looked to be off the boil.
And with Hernandez scoring the winner and another attacking midfielder Pawel Cibicki performing well since coming into the side, Christiansen may perhaps be hoping that Saiz's absence has a positive impact on the Spaniard, as he will be aware that there a number of players vying for his place hitting a good patch of form right now.