Background: Queens of the Stone Age are an American rock band formed in 1996 in Palm Desert, California. The band's line-up includes founder Josh Homme (lead vocals, guitar, piano), alongside band members Troy Van Leeuwen (guitar, lap steel, keyboard, percussion, backing vocals), Michael Shuman (bass guitar, keyboard, backing vocals), Dean Fertita (keyboards, guitar, percussion, backing vocals), and Jon Theodore (drums, percussion). Formed after the dissolution of Homme's previous band, Kyuss, Queens of the Stone Age developed a style of riff-oriented, heavy rock music. Their sound has since evolved to incorporate a variety of different styles and influences, including working with ZZ Top member Billy Gibbons, Nirvana drummer and Foo Fighters frontman Dave Grohl, and Screaming Trees frontman Mark Lanegan who has been a steady contributor to the band.
Context: Foo Fighters frontman and former Nirvana drummer, Dave Grohl, joined in late 2001 to record drums for their third album. Songs for the Deaf was released in August 2002, again featuring Lanegan, along with former A Perfect Circle guitarist Troy Van Leeuwen to the touring line-up following the album's release. Also featured on Songs for the Deaf for the final track "Mosquito Song" were former A Perfect Circle bassist Paz Lenchantin on viola and piano, and Dean Ween on guitar.  This record was supposed to sound bizarre--like lightning in a bottle. We also were extremely fucked up. It even sounds that way to me, like a crazy person. The radio interludes are supposed to be like the drive from L.A. to Joshua Tree, a drive that makes you feel like you're letting go--more David Lynch with every mile.  Songs for the Deaf was a critical hit and was certified gold in 2003, with sales of over 900,000. The singles "No One Knows" and "Go with the Flow" became hits on radio and MTV, with the former just outside the Billboard Top 40. "No One Knows" and "Go with the Flow" were also featured on the first iterations of the popular video games Guitar Hero and Rock Band (respectively).  The Songs for the Deaf tour culminated in a string of headline dates in Australia in January 2004. Grohl returned to his other projects and was replaced on the European leg of the tour by former Danzig drummer Joey Castillo, who joined the band full-time. After the tour, Homme fired Oliveri, as he was convinced that Oliveri had been physically abusive to his girlfriend: "A couple years ago, I spoke to Nick about a rumor I heard. I said, 'If I ever find out that this is true, I can't know you, man.'" Homme considered breaking up the band after firing Oliveri, but found a new determination to continue. Oliveri countered in the press that the band had been "poisoned by hunger for power" and that without him, they were "Queens Lite." He later softened his opinion and said: "My relationship with Josh is good. The new Queens record kicks ass." The two reportedly are still friends and as of October 2006, Oliveri was interested in rejoining the band. Oliveri later contributed to a Queens of the Stone Age for the first time in nine years, contributing backing vocals to the band's sixth album, ...Like Clockwork.
Question: Why was Grohl replaced?. Whats the answer?
returned to his other projects