Wilco [ tickets ], which was set to kick off its fall tour tonight (8/14) in Minnesota, has been forced to postpone the first two shows of the outing while guitarist Nel Cline battles through a bout with the chicken pox.

"He is slowly on the mend but is not quite there yet," the band reported on its website as a way of explanation for the postponement of tonight's show in Duluth, MN, which is now set for Sept. 4, and Wednesday night's (8/15) concert in Winnipeg, Manitoba, which has been pushed back until sometime next year.

Assuming Cline is cleared for action, the band's summer/fall trek now kicks off Aug. 17 in Calgary, Alberta, with 18 cities on the map through late September as the group continues touring in support of this spring's "Sky Blue Sky." All dates are shown below.

"Sky Blue Sky," the band's seventh studio album, follows 2004's "A Ghost is Born." The group self-produced the new set in its own Chicago studio, with TJ Doherty (Sonic Youth, The Hold Steady) handling recording chores and Jim Scott (The Red Hot Chili Peppers, Dixie Chicks) doing the mixing.

The album arrived on The Billboard 200 album chart in the No. 4 spot, marking the band's highest debut ever.