The Avett Brothers' bass player, Bob Crawford, is taking time off from the group to focus on his 22-month-old daughter, Hallie, who is battling a brain tumor. The little girl began having seizures a month ago, which is when the tumor was first discovered.

"Surgeons were able to remove 90% of the tumor and decided to stop there as her vital signs were unsteady," Bob shares on the band's website. "Following surgery, she suffered a stroke. Her condition was critical for the next several days as her brain continued to swell. In an attempt to save her remaining good brain she was placed in a coma for five days."

Hallie has already undergone a second surgery and continues to fight for her life. "The tumor is a Grade 3 Ependymoma," her dad explains. "This is a very rare, but deadly brain tumor that affects roughly 100 children a year in the United States. We do not know what Hallie's next step is in her treatment. Her situation is very fluid and there are a number of complicating factors, but we do know that she is fighting hard every day."

The multi-instrumentalist is grateful for the support from friends and fans. "My wife Melanie and I would like to thank everyone for their love, care, and support during the most difficult time in our lives. I would like to thank everyone for their understanding of the gravity of this situation and ask for respect to our privacy. When people ask us what they can do to help, we ask them to pray for Hallie's recovery. We feel that God has already worked miracles through Hallie and we pray they keep coming."

While it's undetermined when he will return to the band, Bob recently told The Boot the Avett Brothers are working on the follow-up to their 2009 album, 'I and Love and You,' but are in no rush to release new tunes. "We used to put out an album a year, but now we are on a longer cycle. That means more time for the songs to mature and grow after they are written. This is just the next step for us, whatever that is."

There's no word yet on who will take over as bass player for the band while on tour. The Avett Brothers upcoming concert schedule includes shows in Tennessee, North Carolina and Texas. See their concert schedule here.

Avett Brothers Perform Live in Our Studio

%VIRTUAL-globalVideoEmbed-{"videoIds":"517556109","width":"476","height":"357"}%

More From TheBoot