Spring Training Blog
Check our daily spring training blog with updates on everything our team of writers and analysts are seeing and hearing at the ballpark, plus news tidbits from around the baseball world. Blog
But Willis said he has been feeling well on and off the mound.
"I have no idea, but [the doctors] didn't like what they saw in the blood," Willis said. "This is not something where I'm too amped up and I don't know where I'm at, and I'm running sprints up and down the parking lot."
General manager Dave Dombrowski said he could not provide details about Willis' medical condition or treatment because of privacy regulations.
However, two doctors in the Detroit area interviewed by the Detroit News said there is no blood test available to diagnose anxiety.
"I can't speak of the specific situation, but to the best of my knowledge, you cannot diagnose an anxiety disorder by a blood test," Hiten Patel, a psychiatrist at William Beaumont Hospital, told the newspaper. "Most psychiatric conditions cannot be diagnosed by blood tests, and anxiety disorder cannot be diagnosed in such a way."
Taft Parsons, the medical director of the Kingswood Hospital, told the newspaper that anxiety might be a symptom of another medical condition that could be diagnosed with a blood test.
"There's no anxiety disorder, no psychiatric disorders, which are diagnosed by blood tests," Parsons told the newspaper. "But [anxiety] would not be the disorder itself. Only a symptom."
The team said Zumaya's placement on the 15-day disabled list was retroactive to March 27. The Tigers also returned the contract of left-handed pitcher Kyle Bloom to the Pittsburgh Pirates.
Tigers manager Jim Leyland had earlier said Zumaya was unlikely to start the season in Detroit. The right-handed pitcher was considered for the closers job but felt soreness after an appearance on March 2 against Florida Southern College.
"When we get him back, I want him for good," Leyland said. "So we're going to take all the steps to make sure that he's ready to pitch, ready to pitch back to back, and we're in the process of doing that."
Zumaya has pitched three innings this spring, including one in a minor league game Friday, without allowing a hit.
"He feels good, but we're also in a position where we do not want to rush him whatsoever," said Dombrowski, who added Zumaya will be limited to minor league appearances for the rest of the spring.
In 2007, Zumaya tore a tendon in his right middle finger in April. Later that year, he hurt his right shoulder in an accident at his home and didn't pitch the remainder of the season after undergoing reconstructive surgery.
Last year, Zumaya appeared in 21 games and was 0-2 with a 3.47 ERA before sustaining a season-ending fractured shoulder in August.
Bloom, a Rule 5 selection, was returned to the Pirates after attempts to trade him failed, Dombrowski said. Following the roster moves, 35 players remain in major league camp with the Tigers.