The Czech international signed a one-year deal with Blues when moving from Spartak Moscow in the summer.
The 31-year-old has earned praise from manager Alex McLeish for his performances since replacing the injured Scott Dann in mid-January.
But Jiranek is in no hurry to discuss his future.
He said: "I know that my contract expires in the summer. We will see what happens.
"I would prefer not to discuss it at the moment because I would like to concentrate on the remaining fixtures and we still have some difficult games to play.
"When the season is finished, we can come back to the subject."
Source: PA
Source: PA