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Houston cornerback D.J. Hayden remains hospitalized in "stable, yet critical" condition after tearing a vein in a collision with a teammate during practice.

Team physician Dr. Walter Lowe said in a statement from the school Thursday that the senior was taken by ambulance to Memorial Hermann Hospital after the collision late Tuesday afternoon. Hayden was rushed into immediate surgery for a tear of the inferior vena cava, the large vein that carries blood from the lower half of the body to the heart.

Lowe says that type of injury is fatal "95 percent" of the time. He says such an injury is usually linked to high-speed motor vehicle accidents.

"This injury has never been seen or reported in association with a football injury," Lowe said.

Lowe complimented the quick response by the team's trainers, paramedics, the Memorial Hermann trauma team and operating surgeon Dr. John Holcomb. The statement from the school said Hayden was alert, but still recovering in the intensive-care unit.

"We are very fortunate to have some of the nation's top physicians and medical facilities just minutes away from our campus," first-year coach Tony Levine said, "and I would like to extend our appreciation for their efforts on Tuesday evening."

Hayden leads Conference USA with four interceptions and had returns for touchdowns in consecutive games against SMU and UTEP earlier this season. He was named the league's Defensive Player of the Week on Oct. 29 after picking off two passes in the 45-35 victory over the Miners.

"D.J. is a tremendous young man and has been a great asset to our program, both on and off the field," Levine said. "I ask that everyone continue to keep D.J. and his family in their thoughts and prayers."

The 6-foot Hayden transferred to Houston after helping Navarro College win the 2010 national championship. In his first season in Houston, Hayden led the team with 11 pass breakups and five forced fumbles, helping the Cougars finish with a school-record 13 victories and a No. 18 national ranking.

Case Keenum, that team's record-setting quarterback who now plays for the Houston Texans, was getting updates on his phone from friends on Hayden's condition.

"Great player, better guy," Keenum said. "I know his family really well. My family got to know his family, just being at the games and sitting together a bunch. We've felt for them and we've been praying for them. It's nothing short of a miracle that he's still around."

The Cougars (4-5, 3-2 C-USA) have three games left in their 2012 regular season, starting with Saturday's game against Tulsa (7-2, 5-0).