Grateful Dead co-founder Phil Lesh has been diagnosed with bladder cancer, causing him to cancel two upcoming concerts, which he announced Saturday.

In his statement on the website for Terrapin Crossroads, his restaurant and concert venue in San Rafael, California, Lesh said he was diagnosed in early October and has been in Scottsdale, Arizona over the past few weeks at the Mayo Clinic receiving tests. Luckily the tumors are not aggressive and he will have surgery to have them removed.

Lesh had two shows scheduled for Oct. 24 and 25, but he did go onto say that the concerts will be rescheduled as soon as possible.

The Phil & Friends show was also set to feature Chris Robinson from the Black Crowes.

The Grateful Dead is widely considered to be one of the most influential bands in the history of rock music acquiring legions of fans that would follow them from city to city referring to themselves as Deadhead's.

He formed the group Phil Lesh & Friends after the disbanding of the Grateful Dead following the death of Jerry Garcia in 1995.