NICKEL CREEK, Red Butte Amphitheater, Sunday.

In the case of Nickel Creek, one plus two does not necessarily equal three.

More and more, that "one" is Chris Thile, the exceptionally talented mandolin/banjo player for Nickel Creek, who played to a sold-out crowd at the Red Butte Garden Ampitheater Sunday night.

While the band is still billed as a trio, if Sunday's show is any indicator, the group has become Thile and his "bandmates," as he called them multiple times.

The performance even had an eerie sense of a pending split, something probably unlikely for the three members — siblings Sean Watkins, the guitarist, and fiddler Sarah Watkins, are the aforementioned bandmates — who have played together for more than 15 years.

Still, with Thile's dominance of the stage and a relative lack of engagement from the Watkins, especially Sean, something seemed . . . disconnected.

Two years ago, the trio were chatty with each other and the crowd, jawing with a good (and annoying) dose of bubbly enthusiasm. This time, despite occasional bursts of giggles from Sarah and some brief introductions to songs by somebody other than Thile, the band's camaraderie was replaced by professional restraint.

There are other indicators — such as Thile's recent relocation to New York City, or Sean and Thile's strong solo efforts in recent years — that seem to demand a break-up of the band, but are best left to rumor mills and Internet theorists. Because on Sunday night, the band still delivered a strong, and expectedly entertaining, performance.

Although started as a pre-teen bluegrass group, Nickel Creek has grown with age, and the evolving music now has a heavy dose of pop immediacy and confessional lyricism. Both were most apparent on such songs as "Somebody More Like You" and "Helena," the latter a bitter break-up song that Thile claimed was not personal.

Heartache in a WB drama way was a prevailing theme, and it was delivered best when Sarah sang lead on "Sabra" and "You Belong To Me." Her vocals, in fact, outstrip many of her contemporaries in bluegrass or country circles, and whenever she sang it was a welcome, and beautiful, exception to Thile's too-clean singing.

Cover songs also played a starring role in their set list, with everyone from Tim O'Brian ("When You Come Back Down") to Gillian Welch & David Rawlings ("Wayside") to Randy Newman ("Short People") given the Nickel Creek treatment. Most notable, however, was their version of Britney Spears' "Toxic," an entertaining and creative interpretation that could have only been improved by having Sarah, and not Thile, sing the lead vocals.

But again, this has become Thile's band, and when he wants to sing lead he most likely will.

That may be the best thing for him, but maybe not for Nickel Creek.

---

E-mail: jloftin@desnews.com