Three Days Grace endured a bit of turmoil and internal drama this year, with frontman Adam Gontier exiting in January and some very frank commentary between he and the remaining band members being exchanged publicly. In the end, Gontier explained he was quitting of his own accord because he simply wanted to do something else and his former band moved on, pulling in My Darkest Days' Matt Walst to handle vocals for their already booked dates. The pairing with Walst appears to be going well as the Canadian rockers have added a batch of new shows to their North American headlining tour.

Walst, the brother of Three Days Grace bassist Brad Walst, first appeared on the group's co-headlining run with Shinedown earlier this year. He's remained with the band through more shows and scattered festival appearances this spring. The group has stated that they will make a decision on their future once touring is complete, but with more shows continually being added, that decision may not come for some time.

Three Days Grace released their 'Transit of Venus' album last year. It's already generated the hit singles 'Chalk Outline' and 'The High Road.' As for My Darkest Days, they've been writing toward their next album awaiting Walst's return to complete the disc. The frontman has been in the studio with MDD during breaks in the Three Days Grace schedule.

The new batch of Three Days Grace dates are posted below. The full tour itinerary can be seen here.

Three Days Grace 2013 North American Summer Headline Tour Dates

7/27 -- Syracuse, N.Y. -- KROCKATHON
8/9 -- Ft. Wayne, Ind. -- Piere's
8/11 -- Cleveland, Ohio -- House of Blues
8/16 -- Cincinnati, Ohio -- Bogart's
8/17 -- Sedalia, Mo. -- Missouri State Fairgrounds
8/18 -- Fayetteville, Ark. -- Arkansas Music Pavilion
8/25 -- Boise, Idaho -- Knitting Factory
8/27 -- Seattle, Wash. -- Showbox SoDo
8/28 -- Missoula, Mont. -- Wilma Theater
9/26 -- Sayreville, N.J. -- Starland Ballroom
9/27 -- Hampton Beach, N.H. -- Hampton Beach Casino Ballroom