Mumford & Sons receive the award for British Group from Berenice Marlohe on stage during the Brit Awards 2013 on February 20, 2013 in London, England.

Though Bonnaroo has a formidable lineup of acts gracing its stages this weekend, two acts -- Mumford and Sons and Earl Sweatshirt -- have cancelled appearances at the festival.

Mumford and Sons announced today (June 13) that it will cancel its appearance at the Tennesee fest, hot on the heels of bassist Ted Dwane's surgery for a blood clot on the surface of his brain.

According to the band on Facebook, Dwane's surgery went well and he's "on the road to a full recovery," but in order to give him time to recover, the four-piece has nixed its appearance at the festival, as well as a set at Colorado's Telluride Bluegrass Festival next week.

"If we could've we would've, you know that about us," the post read. "We trust that you can respect our collective desire to encourage Ted to make a full recovery, and that this is based purely on the medical advice we have received."

Meanwhile, Odd Future rapper Earl Sweatshirt has also cancelled his Bonnaroo show, due to pneumonia. "To everyone at bonnaroo: im sorry i cant make it im really really f***ing sick but i will make it up to tennessee as soon as i possibly can," he tweeted.

Though a replacement for Mumford has not yet been named, Earl Sweatshirt will be replaced by Brooklyn indie rockers DIIV. The band was formerly scheduled to perform today, but have instead taken the rapper's slot due to flight delays.