Freshman quarterback Corey Nielsen is being withheld from Hawai'i football practices while doctors determine the cause of an irregular heartbeat.

During Wednesday's practice, Nielsen complained of shortness of breath.

"I couldn't catch my breath," Nielsen said. "That never happens to me."

He underwent an electrocardiogram.

"They said I have an overworked heart or an enlarged heart or something," Nielsen said.

He is scheduled for a stress test and an echocardiogram next week.

He said he has not experienced any problems in the past.

"I think it's precautionary," Nielsen said. "I feel good. I feel I can practice, but I don't want to risk my health."

Nielsen attends practices, watching from the sideline.

"I'm bummed I can't practice," Nielsen said.

Nielsen said he had prepared to redshirt this season. Greg Alexander, a senior, is the No. 1 quarterback. Brent Rausch, a junior, and Shane Austin, a third-year sophomore, are the top backups. Bryant Moniz also has been getting a lot of reps.

"It's not a bad thing to redshirt," Nielsen said.

OL HANSEN GETS REPS

Austin Hansen is proving to be a capable backup on the offensive line.

The past two days, he has worked as the No. 1 left guard in place of Ray Hisatake, who completed work for Summer Session II.

"He's getting some good reps," right tackle Laupepa Letuli said.

Hansen is capable of playing each position on the line.

"It's fun to get the reps and know what's going on in case anything happens," Hansen said.

The Warriors are trying to build depth. The starting line — left tackle Aaron Kia, Hisatake, center John Estes, right guard Raphael Ieru and Letuli — are all seniors.

Hansen is still in his honeymoon period — literally. He and his long-time girlfriend Rachel were married last month.

"We grew up together," Hansen said. "I've known her since I was 8 years old."

He proposed by recreating their first date.

"We went to a restaurant down by the beach where we live in Orange County," Hansen said. "That's where I proposed to her."

LINEBACKER ADDED

Outside linebacker Joseph Malabuyoc has been added to the training-camp roster.

Malabuyoc had been told he would join Aug. 24, the first day of UH's fall semester, when the NCAA's roster limits are lifted. But a roster spot opened. Because he already had taken his medical examinations, he has been allowed to practice.

Malabuyoc is from Vancouver, British Columbia. He learned of UH through his high school track coach, a Farrington High graduate. He is not on scholarship.

"I don't have a green card, so I pay a little more for tuition than everybody else," Malabuyoc said. "Other than that, everything is the same — the price of books, housing."

Malabuyoc, who is 6 feet and 230 pounds, has been practicing on both the left and right sides.