The Czech Republic international has been defying the problem to continue playing for several weeks but had to be substituted in the early stages of Blues' last game at Wigan.
Blues have taken advantage of the international break, sending the 31-year-old to undergo surgery.
Manager Alex McLeish confirmed: "Jiranek had a minor operation on his toe. He has been playing with that discomfort for the past eight to 10 weeks.
"We had to do something about it. He came off after 15 minutes of the Wigan game. He was clearly in distress and also being restricted in his running.
"He is a doubt at the moment for the weekend."
Source: PA
Source: PA