As guitarist Noel Gallagher "is suffering from the effects of whiplash and shock" following a car accident Tuesday in Indianapolis, the band has postponed upcoming concerts in Philadelphia and Boston. A decision on rescheduling those shows, planned for Friday at the Tower Theater and Saturday at the Fleet Pavilion, respectively, will be made early next week, according to a statement.

A doctor at the Indiana University School of Medicine prescribed further painkilling drugs for Gallagher. He was ordered to allow three days of complete rest "in order to lay the basis for as quick and complete a recovery as possible, and to prevent any long term or permanent effects from the accident," the statement reads.

As previously reported, Gallagher, bassist Andy Bell, and touring keyboardist Jay Darlington were in a taxi that was involved in a head-on collision with another vehicle. All three were treated for shock, cuts, and bruises and released from a local hospital. The band initially canceled last night's (Aug. 7) appearance in Indianapolis, and Darlington was expected to seek further treatment for an injured hand.

Oasis is expected to return to the road on Sunday at New York's Roseland Ballroom. The U.K. group is touring in support of its recent Big Brother/Epic album, "Heathen Chemistry," which features the hit U.K. singles "The Hindu Times" and "Stop Crying Your Heart Out."