Koch has now recovered from injury and remains front of mind for Bielsa.
"He (Llorente) has played well, he hasn't had any bad games," said Bielsa, whose side face Liverpool at Elland Road on Monday.
"He's had a performance level that has improved every single time we have played. He started playing well and from there onwards he's been playing better.
"Llorente, as well as Koch, in the first part of the season, they have been high points of our season."
Germany's Koch, signed for around £13million from Freiburg, recently returned to action after knee surgery and could make his first start since December against Liverpool in the absence of suspended skipper Liam Cooper.