Good thing we have tickets to see Aerosmith in Chicago later this month, because at the rate the band is going, this tour may be its last.

Aerosmith lead singer Steven Tyler, 61, is recovering from a broken shoulder and minor head and neck injuries after falling off stage Wednesday at the annual Sturgis Motorcycle Rally in Rapid City, S.D. Apparently the last 18 scheduled dates of the band’s summer tour are in doubt now. And that’s OK, since I saw Aerosmith in concert twice before in the ’90s and only got tickets this time because a friend was able to procure several lawn tickets for $15 each. (With ZZ Top opening for Aerosmith, the $15 classic-rock concert sounded like a great deal to me.)

What’s amazing to me is the number of health-related injuries the Boston band has incurred during this tour. I found this rundown of Aerosmith medical problems on MTV.com:

The Tyler tumble is the latest injury to befall the veteran hard rockers on the road. In February, the international kickoff in Venezuela was canceled because of an infection sustained by (lead guitarist Joe) Perry that required emergency surgery related to a knee replacement he underwent in 2008.

Last month, the band was forced to cancel seven shows due to an unspecified injury, rumored to be a pulled leg muscle, sustained by Tyler onstage. That was followed by bassist Tom Hamilton’s departure for a handful of dates in order to recuperate from unspecified “non-invasive surgery.” Earlier in the trek, guitarist Brad Whitford was forced to sit out the initial dates due to a head injury, which required surgery, sustained when he was getting out of his Ferrari.

Several months before the tour, Tyler checked into rehab to recuperate from foot surgery. In March he contracted pneumonia, which pushed back sessions for the group’s new album.

It seems time has caught up with these aging rockers.