The reunited Van Halen have been forced to postpone four upcoming dates of their U.S. tour due to an unspecified medical condition affecting guitarist Eddie Van Halen. A statement issued by tour promoter Live Nation on Monday afternoon (March 3) explained that concerts in Dallas, Cincinnati, Baltimore and Raleigh, North Carolina, have been postponed and rescheduled for April.

“According to Eddie Van Halen’s physician, he is undergoing a battery of comprehensive medical tests to determine a defined diagnosis and recommended medical procedures,” read the release.

A Live Nation spokesperson could not elaborate on the medical condition that has sidelined the guitarist, whose stint in a rehab facility last fall delayed the long-awaited reunion with founding vocalist David Lee Roth.

Due to the medical issues, the show that was scheduled to take place Monday night at the American Airlines Center in Dallas has been rescheduled for April 24, Wednesday’s show at the U.S. Bank Arena in Cincinnati will take place April 22, Friday’s show at the RBC Center in Raleigh has been rescheduled for April 13, and Sunday’s show at the 1st Mariner Arena in Baltimore has been bumped to April 15.

The Live Nation spokesperson said the tour is expected to pick up the previously scheduled dates beginning on March 11 in Charlottesville, Virginia, and, for now, no other dates have been affected. According to the band’s Web site, the tour is currently slated to run through an April 19 date at the Mandalay Bay Events Center in Las Vegas.