Sammy Hagar [ tickets ] and Lynyrd Skynyrd [ tickets ] have canceled several upcoming "Party of a Lifetime" co-headlining tour dates so that Skynyrd guitarist Gary Rossington can recover from a physical ailment.

The move comes after doctors advised Rossington to "immediately rest in order to combat medical fatigue," according to a press release. The guitarist underwent heart surgery in February.

The canceled dates are Aug. 1 at Oak Mountain Amphitheater in Pelham, AL; Aug. 2 at Hi-Fi Buys Amphitheatre in Atlanta; Aug. 3 at the William Floyd Amphitheatre in Anderson, SC; and Aug. 5 at SETEC Amphitheatre in Beaumont, TX. Refunds are available at the point of purchase.

Hagar and his band, the Waboritas, will play without Skynyrd on Aug. 6 in Corpus Christi, TX.

Skynyrd plans to make up the Aug. 2 and Aug. 3 shows without Hagar. The new Atlanta date is set for Sept. 10; a make-up date for the Aug. 3 show hasn't been set.

Veteran Southern-rock outfit Lynyrd Skynyrd is backing its May 20 release, "Vicious Cycle," which is the group's first new studio set in four years. The album was originally due out on May 6, but the group postponed the release following Rossington's quintuple-bypass surgery.

"Sammy & the Wabo's Live Hallelujah," Hagar's new album, landed in stores on May 20. He recorded the set during last summer's co-headlining run with his fellow Van Halen alumnus, David Lee Roth--or, as a recent Hagar press release refers to Roth, "what's-his-name."