The 15 concerts plug a gap in Papa Roach’s schedule before a quick jaunt to Europe the last week of May. The extended tour commences April 20 in Quebec City, and includes stops in Montreal, Toronto, Detroit, San Francisco, Phoenix and Las Vegas.

Fear Factory comes on board to replace Orgy, which was forced to drop off the bill when Amir Derakh, the band’s synth guitarist, was diagnosed with a severe case of mononucleosis and ordered by doctors to stop touring for the time being. Derakh is expected to make a full recovery and the band plans on touring in May and June.

As much as Derakh’s illness put a severe crimp in Orgy’s plans, it provided an opportunity for Fear Factory to get some additional exposure after recently gigging on the SnoCore Rock tour with Kittie, Union Underground, and Slaves on Dope.

Papa Roach has been on the road constantly in support of its DreamWorks debut, Infest. Following Raid the Nation, the rockers from Vacaville, Calif., are set to join the main stage lineup of Ozzfest 2001, which kicks off June 8 at the New World Music Theatre near Chicago.