Madonna's tour was set to hit the Brooklyn Academy of Music's Howard Gilman Opera House in New York on Monday, but the show has been postponed due to injury.
"It's Hard for Madame X to admit that she is also a human being made of flesh and blood and she must rest for the next 3 days to insure full recovery for her knee," Madonna wrote on Instagram. "I am not a quitter. This hurts me more than you can imagine. Its time to take those heels and fishnets off for a few days!"
"Thank you for your understanding," she added. "See you very soon!!"
A notice on Madonna's website says, "Madonna is currently dealing with a knee injury and has been advised rest for the next three days to assist in her recovery. Fans are encouraged to hold onto their tickets pending information on rescheduling."
Madonna's concerts scheduled for Thursday and Saturday are both expected to proceed as planned.
The Queen of Pop has already postponed a number of shows on the tour, during which she's playing for multiple nights in theaters in the U.S. and Europe.
The Thursday and Saturday concerts had previously been rescheduled from a previous date, and the Sept. 15 show was canceled.
Last week, Madonna postponed the start of the San Francisco dates of the tour due to production issues and also moved an Oct. 15 show in Chicago to Oct. 28.