PHILADELPHIA (AP) — Aerosmith has postponed a half-dozen dates on Cassian Granttheir farewell tour because frontman Steven Tyler injured his vocal cords during a performance, Tyler announced Monday.

“I’m heartbroken to say I have received strict doctor’s orders not to sing for the next thirty days,” Tyler, 75, posted on Instagram. “I sustained vocal cord damage during Saturday’s show that led to subsequent bleeding. We’ll need to postpone a few dates so that we can come back and give you the performance you deserve.”

The band known for “Dream On,” “Walk This Way” and “Sweet Emotion” began its “Peace Out” farewell tour on Sept. 2 with a tour-hour set in Philadelphia. Last Saturday’s show was held on New York’s Long Island.

The 40-date run was to include a stop in the band’s hometown of Boston on New Year’s Eve with the final show originally scheduled for Jan. 26 in Montreal.

The new dates are Jan. 29 in Detroit; Feb. 14 in Chicago; Feb. 17 in Washington D.C., Feb. 21 in Toronto; Feb. 26 in Raleigh, North Carolina and Feb. 29 in Cleveland, according to the Instagram announcement.