Wilco drummer Glenn Kotche has completed "Anomaly," a 23-minute piece for the Kronos Quartet that will premiere in San Francisco in October. The seven-movement composition came to life when Kronos member David Harrington approached Kotche after the 2006 release of the latter's latest solo album, "Mobile."

"I really dug in and spent a lot of time, because I've never written outside of percussion before," Kotche tells Billboard.com. "That was basically my November through the end of January."

"It's very percussive," Kotche says with a laugh when asked to describe the sound of the piece. "I'm not toning it down. I'm playing a multiple-percussion kit. It's really rhythmic; there's a lot of energy. Some parts are beautiful; things I couldn't play on drums. That's the way I treated the whole thing: four players in the quartet. I have each player to act like a limb to explore rhythmic ideas. If I could have a violin be my right hand and a cello be my left foot, what would it sound like?"

The Kronos Quartet's most recent release, "Gorecki's String Quartet No. 3," came out last week via Nonesuch. Kotche, of course, is about to begin touring in support of Wilco's new album, "Sky Blue Sky," due May 15.

In addition, Kotche has begun recording a new album with his duo, On Fillmore.