PHOENIX — Arizona Diamondbacks left-hander Doug Davis has been diagnosed with thyroid cancer.

"We don't know much, other than he does have thyroid cancer," team president Derrick Hall said in a telephone interview today. "It's saddening. It was a complete surprise to the entire organization, and to him."

The 32-year-old Davis still planned to make his scheduled start against Colorado in an exhibition at Chase Field tonight. Hall said Davis would take his regular turn in the rotation on April 3 at Cincinnati, in the first series of the regular season.

Davis is expected to undergo surgery on April 10, Hall said. The defending NL West champions don't know when Davis might return.

"After that, it's too difficult now to predict any timing related to it," Hall said.

"There is a chance he won't be ready this season," Hall said. "It dramatically changes the outlook. Naturally, we'd rather Doug be in the rotation, but we do have good, viable options."

Hall said Davis met with teammates on Friday. The pitcher is scheduled to speak to the media after Friday night's game.

"He's in a terrific frame of mind," Hall said.