ALAMEDA -- Rookie cornerback D.J. Hayden is in a local hospital as a result of an abdominal issue that surfaced last week, Raiders coach Dennis Allen said Tuesday.
Hayden is expected to miss the remainder of the Raiders offseason workouts and practices, but he should be ready to go again when training camp begins in late July.
A Raiders spokesman said Hayden was admitted to the hospital late last week and that he underwent a procedure to remove scar tissue from his abdominal region.
Allen said he isn't sure whether there's any correlation between Hayden's current situation and the ruptured vein Hayden suffered last November during a practice at the University of Houston.
"We can't rule that out, obviously, but right now I don't know exactly what the correlation is to it," Allen said. "But we don't anticipate it being an issue."
Hayden underwent surgery to repair the ruptured vena cava, which supplies blood to the heart from the lower body. He was cleared by doctors to resume football activities last month after surviving an injury that is 95 percent fatal, by some accounts.
A phone call to the doctor that performed the life-saving surgery on Hayden at Memorial Hermann Texas Trauma Institute was not returned.
Hayden participated in practice last week, when the Raiders began their organized team activities. Allen said Hayden's symptoms surfaced soon thereafter.
"My stomach hurts so bad right now," Hayden said via Twitter on May 20, the first day of OTAs.
Safety Usama Young said he was on the field with Hayden at the start of OTA and sensed something wasn't quite right.
"You could tell he was under the weather," Young said. "I thought that was it; he was under the weather. ... It took me by surprise. I didn't think he was that sick."
Young said he has communicated with Hayden via text message and that Hayden said he is doing "a lot better."
Linebacker Nick Roach said he didn't even know that Hayden had been hospitalized.
Roach said he noticed Hayden with a hoodie pulled down over his head. Then again, a lot of players do that early in the morning, he added.
"I didn't know the extent of it," Roach said.
The Raiders selected Hayden with the 12th pick of the 2013 NFL draft. They are counting upon Hayden to crack the starting lineup at some point.
During recent interviews, Hayden said he felt good and that the only time he thinks about the injury he suffered in November is when he gets asked about it.
Allen said Hayden's absence, combined with a calf injury to cornerback Tracy Porter, leaves the Raiders thin at cornerback and makes it all the more difficult for Hayden to succeed from the outset.
"It's obviously not a good thing, from a football standpoint," Allen said. "As a rookie, you need all the reps you can get and all the work you can get."
Young said Hayden "looked the part" from what little he saw of Hayden before he was hospitalized.
"He looked pretty good," Young said. "It looked like he was moving pretty well. He looked good, looked fast, looked quick, had good hands."
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