It will likely be four to six weeks after the surgery before Davis is able to pitch again.
During a routine physical on Feb. 6, Dr. Mark Baldree discovered a firm nodule on Davis' throat. That led to an ultrasound and then a biopsy. When the biopsy was taken the person performing it told Davis he thought there was a 75-85 percent chance it was a tumor.
One of the D-backs' team physicians, Roger McCoy, was the one who gave Davis the news on Wednesday by phone.
"It was not a big surprise," said Davis, who said he cried and was down after the call. "It's just something that I have to fight through."
When Davis called D-backs manager Bob Melvin early Thursday to inform him of the findings, he quickly changed subjects.
"As I was trying to grasp the news, he was trying to talk me into his next start," Melvin said. "I had a tough time getting by it. I had a hard time focusing on baseball [on Thursday]. I was thinking about Doug all day long."
Davis' start on Friday did not go as he wanted, as he allowed eight runs on nine hits in just 2 2/3 innings.
"I really didn't think about it at all," Davis said. "Believe it or not, I really felt like I was executing my pitches. They were just hitting them. It actually takes my mind off the fact that I have thyroid cancer. It's something that baseball's kind of a way to not think about the thyroid cancer, somewhere to get away and not stress about something that's going to take me down for a while but not out for good."
Melvin was asked if he was surprised that Davis wanted to make his first two regular-season starts.
"I was at first, but if you know Doug, it doesn't surprise you," he said.
Davis is one of the more popular players in the Arizona clubhouse. His teammates appreciate the hard work he puts into his between-starts program, including extensive video and statistical scouting.
Davis was acquired by the D-backs from the Brewers in November 2006 and the Phoenix-area resident promptly signed a three-year, $22 million extension that runs through 2009.
"Obviously we're all in his corner," closer Brandon Lyon said. "All of us are just going to support him any way we can."
It's that kind of backing that Davis said will help him get through this challenge. Davis said that Rockies players passed along their prayers to him on Friday.
"I believe the whole game is pulling for me, as I would for them," Davis said. "I'm not going through this alone. I've got all the help in the world, and I'm definitely optimistic about the outcome."
Davis has good reason for optimism, according to team physician Michael Lee, who said Davis should only need one night's stay in the hospital and could feel good within a week and a half following the surgery. While every body is different, Lee said that the extra exertion required of a professional athlete would likely mean a four-to-six-week recovery period.
"It is very curable; it's almost 100 percent curable," said Lee, adding that Davis will need thyroid-replacement medication for the rest of his life, which will not limit him in any way.
A durable pitcher, Davis was 13-12 with a 4.25 ERA in 33 starts in 2007. It was the fourth straight season in which he posted double-digit wins and pitched 192 or more innings.
Davis said both his mother and sister had thyroid cancer and made full recoveries. If Davis wants to look to other baseball players who have overcome thyroid cancer, he won't have to look far.
D-backs director of player personnel Jerry Dipoto underwent a similar surgery in 1994 and went on to pitch that year as well as the next six without suffering any further problems.
"Everyone's body is different and responds to things differently," Dipoto said. "I can't avoid the fact that I had it, that people know about the fact that I had it. But I don't want to talk about my experience, I want his story to be his story and I don't want to intrude in this. I'm here as a resource if he needs something."