Sir Andrew Davis, Lyric Opera of Chicago's music director and principal conductor, will undergo leg surgery next week that will cause him to miss more than a month of performances, the Lyric announced Friday.

Davis, 62, has had pain in his left leg for some time and the surgery, a femoral popliteal artery bypass, is intended to "increase his comfort and mobility," Lyric spokeswoman Magda Krance said.

The surgery will keep Davis from conducting the Sept. 16 opening of the Lyric's 52nd season. Bruno Bartoletti, his predecessor at Lyric who is now Lyric's artistic director emeritus, will replace him for six performances of the David Hockney production of Puccini's "Turandot," the Lyric announced.

Davis was also scheduled to conduct a free concert on Sept. 9 called "Stars of Lyric Opera at Millennium Park." A replacement has not been determined.

Davis, the artistic adviser for the Pittsburgh Symphony Orchestra, will also miss five concerts scheduled for later this month in Greece, Ireland, Cardiff, Wales and in London's Royal Albert Hall. Leonard Slatkin will replace him for those five performances in Europe, the orchestra said.

Davis is expected to return to the Lyric podium to conduct the Renee Fleming Subscriber Appreciation concert on Oct. 6 and then the new production of Richard Strauss' "Salome," which opens Oct. 21.