Drive-By Truckers [ tickets ] have added new dates to a tour now greatly altered by the recent departure of longtime guitarist/vocalist Jason Isbell.

The band--through a message penned by frontman Patterson Hood--announced last week on its website that the group and Isbell would be parting ways immediately. Hood termed the split "extremely amicable" and cited "differing dreams and goals" as the motivator for Isbell's departure.

"We all are wishing him nothing but the absolute best on every step that plays before him," Hood wrote in the posting.

Now short one guitarist, the group will soldier on through the rest of its spring/summer schedule, which now features a few new dates in June and July, most of them in southern states. The trek resumes April 20 in Nashville, with 17 cities on the itinerary--included below--through mid-summer.

Somewhat ironically, Hood had broached the idea of a coming change for the band in a pre-tour posting on the group's website, saying that the group "wanted to go out and do something a little different. Maybe revisit some songs in a different light, maybe try out some new stuff on a smaller scale, maybe tell some stories and sing some songs. Pull up some chairs, have a few drinks and tell some stories to each other and some friends."

Isbell is currently playing a number of solo dates in advance of his debut solo album, "Sirens of the Ditch," due in stores July 10.

Drive-By Truckers are supporting their most recent album, "A Blessing and a Curse," which surfaced last April. The set debuted at No. 50 on The Billboard 200 chart, and is the band's fastest-selling record to date, according to New West.