Anaheim’s Diaz Back in the Thick of It : Prep football: After overcoming blood clots that kept him off the field most of last season, senior fullback leads the 6-1 Colonists against Valencia.

All Brian Diaz could do was stand on the sideline and watch Valencia High’s 43-6 Orange League football victory over Anaheim last season.

He wanted to do more, but he couldn’t.

Diaz, a senior fullback, sat out his junior year because of blood clots in his right calf, a frustrating experience for him and the 2-8 Colonists.

“I couldn’t handle watching on the sidelines,” Diaz said. “I had been playing football since I was 9, and here I was watching. I was helpless.”

But Diaz has returned after taking blood-thinning medication for nearly a year.

And the Colonists’ winning ways have returned with him.

Diaz has rushed for 869 yards in leading the Colonists (6-1, 2-0) to their best start since 1987. Anaheim is tied for first place in the league with Valencia heading into the teams’ Friday night showdown at Glover Stadium.

Anaheim Athletic Director Dan Miller said Diaz hasn’t had to look far for inspiration this season.

“Last year was pretty hard on him,” Miller said. “He lived for football, and it (not playing) is why he’s out there punishing people so much this year.”

Diaz’s blood clot wasn’t properly diagnosed until after his sophomore season. He played on Anaheim’s 10-0 freshman team, and was a second-team all-league pick as a sophomore.

“I had big hopes for my junior year,” he said.

But his right calf, which had started swelling at the beginning of his sophomore season, began to hurt. At first, doctors told him it was a leg sprain.

After the season, Diaz saw another physician, Ursula Iyer of Anaheim, who discovered the blood clot.

Diaz spent a week in the hospital, and began taking blood-thinning medication to clear up the clot.

“My doctor told me I was lucky to be alive,” Diaz said. “The clot was in a vein, and if it broke loose, it could have gone up to my heart.”

The medication dissolved the clot by the summer before his junior season, and doctors cleared Diaz to play just before the start of practice.

Diaz made it through practice and started at fullback and middle linebacker in the Colonists’ season-opener against Fullerton.

Then another blood clot, in a different vein in his calf, ended his season.

“I couldn’t do much of anything,” Diaz said. “I could do some light jogging, but that was about it. No contact.”

He also sat out track season, in which he had showed promise as a pole vaulter. His football future was just as questionable.

“I didn’t want to tell everyone (on the team) that I would be back for sure and I wouldn’t,” he said. “I told them they could still go on and do it without me.”

He continued taking the medication, and Iyer cleared him to play in August, just before the start of practice.

“My other doctors (before Iyer) told me I might never play again,” Diaz said. “But I was happy to get another shot.”

Diaz still takes medication, but has had no problems in his first seven games. His playing time was reduced from two positions--middle linebacker and fullback--to just offense.

“I tried to do too much my junior year,” he said, “and that might have been what caused the (blood clot) problems.”

His calf is still swollen, about two inches larger in circumference than his left calf.

“I think I’m taking somewhat of a risk (by playing),” Diaz said. “You have to take them in life, you have to take them for the team. My teammates do the same for me.”

Anaheim Coach Todd Borowski said Diaz’s bruising tackle-to-tackle running, along with tailback Che Garcia’s speed to the outside gives the Colonists a strong, versatile backfield.

“The line will give Brian four or five yards,” Borowski said, “and then he’ll take four or five more by breaking a tackle.”

Yards will be tough to get Friday night.

Valencia has won the league title eight of the last nine years, and the Tiger defense is traditionally tough against the run.

Diaz and his family have looked forward to the matchup for a long time. His two stepbrothers and two stepsisters attended Valencia. His father, Felix, a print-shop owner, played football at Anaheim for two years.

Win or lose, the season already has been a good one for Diaz and the Colonists. After going 6-14 the last two seasons, they’ve already clinched a winning record this year. A victory in one of their final three games could lock up a playoff spot.

Turning the program around hasn’t been easy, Diaz said.

“It has been tough,” he said. “But we figured we might as well make the best of this season, because we’re never going to play again.”