One week into game action, much has changed in the prep football universe.

Mililani’s path took an unexpected turn with a collarbone injury to quarterback Kini McMillan during a 29-0 win at Kailua. Co-head coach Rod York confirmed the injury.

Injuries are the norm, but this one may have the biggest impact in the OIA Open Division race as long as the talented playmaker is sidelined. York said he hopes McMillan, who entered his senior season with 5,868 passing yards and 69 touchdowns, can return for the postseason.

This weekend, fourth-ranked Saint Louis meets No. 2 Mililani at John Kauinana Stadium on Saturday. The Crusaders are dealing with injuries, too.

“We got Titan (Lacaden) out,” Crusaders first-year head coach Tupu Alualu said of the wide receiver’s ankle injury. “Jordan (Nunuha). Everybody’s got guys out.”

Lacaden and Nunuha were Saint Louis’ top two receivers last season, accounting for 16 of the Crusaders’ 19 receiving touchdowns.

Top-ranked Kahuku has its share of injuries, as well.

“Injuries are a part of the game. Never want to see any player with an injury. My heart goes out to injured players. Praying for a healthy and speedy recovery,” coach Sterling Carvalho said.

The Mililani-Saint Louis connection has been fruitful. York and former Saint Louis coaches Ron and Cal Lee often worked together at neighbor-island football clinics. Alualu saw Mililani’s new co-head coach (and defensive coordinator), Vavae Tata, rise through the years as a player.

The Crusaders are coming off a 14-13 loss at Kahuku, nearly pulling off a rarity. Kahuku almost never loses on its home field with only one loss to a Hawaii opponent on the North Shore since 2007. Defending OIA champion Mililani is also a tough foe on its home field.

“Mililani’s a good team. For me, I just worry about what we can do and what we bring to Mililani. I let my OC (Leonard Lau) and DC (Thom Kaumeyer) worry about that,” Alualu said. “All I ask is that our kids be humble, have effort and discipline, and glorify God.”

Sierra Canyon (Calif.) (0-0) at No. 5 Punahou (1-0)

Friday, 3 p.m.

The mid-afternoon battle at Alexander Field will be the season opener for the visitors from Chatsworth, Calif. It will be a good test for the Trailblazers, who play JSerra Catholic, Oaks Christian and St. John Bosco in consecutive weeks after returning to the continent.

Punahou’s defense is ready to carry most of the weight while the offensive unit gains experience. Linebackers Ko‘o Kia, a commit to Notre Dame, and defensive backs Donny Utu (Stanford) and Dane Kellner have been through many big moments for Punahou, the two-time defending ILH champion.

“Sierra Canyon is a very good, nationally ranked team with top-tier talent,” Buffanblu coach Nate Kia said. “This will be a great test for our young team. Confidence for a young team like ours comes from stacking days of continual development. The season itself is a process, and we have to get better with each game to prepare ourselves for league play.”

According to a tweet from longtime Los Angeles Times high school sports writer Eric Sondheimer, Sierra Canyon coach Jon Ellinghouse boarded a 6 a.m. flight from California to Hawaii on Saturday to see Punahou’s 35-0 shutout of Konawaena. He returned on a 9 p.m. flight out of Hawaii on the same day.

No. 6 Kapolei (1-0) at Lahainaluna (0-0)

Friday, 4 p.m.

It is not often the Lunas host an Open Division team at Sue Cooley Stadium. When the OIA Open schedule revealed a large number of bye weekends, Kapolei coach Darren Hernandez had to hustle.

“We haven’t seen (Lahainaluna) since they haven’t played yet, but we are well aware of their winning tradition and their brand of excellence and toughness. The Open Division has less games and so we were scrambling for opponents as we had five bye weeks, so I inquired with a bunch of neighbor island schools to see if they wanted to play us. Fortunately, Lahainaluna and Kapaa agreed to games,” said Hernandez, now in his 21st season guiding the Hurricanes.

Hurricanes quarterback Tama Amisone remains one of the most elusive offensive playmakers in the state. As a junior in 2023, Amisone passed for 2,501 yards and 33 TDs in 11 games. He also rushed for 1,068 yards (10 yards per carry) and 14 TDs. This presents quite the challenge for Division I Lahainaluna.

“Their quarterback, I think he committed already,” Lunas coach Dean Rickard said. “Everybody knows this is the highest level of competition in Hawaii. Everybody might want to avoid this level. We lost so many seniors (29). Ten of them were starters as sophomores. We have to find our identity.”

Amisone is a San Jose State commit.

Simone Olakauatu (6-3, 300) and Kawika Kaili (5-11, 250) are cornerstones up front. Olakauatu is a third-year starter at guard and defensive tackle. Kaili started at center for three years and has moved to guard.

“What better way than to test ourselves,” Rickard said. “Kapolei is solid, well-coached and disciplined.”

Longtime co-head coach Bobby Watson officially retired after last season.

“Every now and then he’ll check in, start some drills. Scout a little. He’s taking care of his grandkids,” Rickard said. “He’s been coaching since 1978 when I was a freshman in high school. As long as our staff is here, the tradition, philosophy, values and beliefs will never change. You change up to a certain point, but never forget your core.”

No. 1 Kahuku (1-0) at Bishop Gorman (Nev.) (0-0)

Friday, 4 p.m.

The visitors from Oahu’s North Shore won’t be at 100 percent, but they still relish a chance to perform on the big stage. The question will present itself: can Hawaii’s three-time defending state champion neutralize the Gaels’ massive trench men. Bishop Gorman has some of the best talent from across the country, along with arguably the finest weight room — more like a warehouse — in the nation.

“Bishop Gorman is big up front on both sides of the ball. They are the defending national champions for a reason,” Kahuku coach Sterling Carvalho said.

Former Roosevelt and UH football player Chad Kapanui, formerly a coach at Liberty, is the quarterbacks coach at Bishop Gorman. The Gaels are ranked No. 2 nationally by MaxPreps. Kahuku is No. 30.

Kahuku is without All-State Offensive Player of the Year Mana Carvalho (leg injury) for roughly two months, but came up with a dramatic 14-13 win over Saint Louis last weekend.

“Our offense has brought confidence. We only have one returning offensive starter. Seeing the offense come to life in the second half against Saint Louis gave promise and confidence to this young and inexperienced group. They grew up right before our eyes,” Carvalho said.

Tafuna (Samoa) (1-0) at No. 7 Farrington (1-0)

Friday, 7 p.m.

Tafuna’s lengthy stay on Oahu includes a big battle in Kalihi with the Governors. The Warriors’ 41-35 win at Waipahu, which moves up to the OIA Open Division this fall, is a signature moment. A win at Skippa Diaz Stadium would certainly be another.

“Tafuna is a solid football team that just beat a good Waipahu team. They’ve got really good athletes that can present problems for many teams,” first-year Farrington head coach Mike Lafaele said.

Originally, Tafuna was going to play one game in the islands.

“They reached out to us last year about scheduling a second game after they secured the Waipahu game, and we agreed to play each other,” Lafaele said.

Farrington’s balanced offense was on display in a 35-12 win over D-I powerhouse Kapaa last week.

“My confidence comes from God. We’re blessed and thankful to have the coaching staff and players that He has put together. I’m excited to see all our guys fly around and make plays,” Lafaele said. “We’ve worked extremely hard in the off-season.”

Mission Viejo (Calif.) (0-0) at No. 8 Kamehameha (1-0)

Saturday, 7 p.m.

The visiting Diablos are ranked No. 28 nationally by MaxPreps. This will be their season opener, followed by a home game against Santa Margarita (Calif.) on Aug. 24.

Kamehameha grinded out a 10-3 win over Leilehua last weekend, using a balanced offense and tenacious defense to stymie the Mules’ hurry-up offense.

No. 10 ‘Iolani (1-0) at No. 9 Leilehua (0-1)

Saturday, 6 p.m.

The Raiders opened the season with a 45-0 rout of Kalani, a good sign for a young roster.

“We got our young guys in to get playing time, get experience. Overall, I thought we’re pretty good on our assignments and how we executed, so that was good,” Raiders coach Wendell Look said.

The Mules were relentless defensively against Kamehameha.

“They’re very aggressive. They run well to the ball. The matchup is always up front for us. We’ve got to be able to control up front, assignment-wise. We’re not going physically dominate anybody,” Look said. “We’ve got Elias Kagawa playing center. We lost our starting center, Jonah Takayama, he’s injured again. Second year in a row. Elias would’ve started at guard. For us, that’s our main guy in the OL. It’s a matter of them playing together and being on the same page. That takes repetitions and experience.”

Musical chairs

Last year, the OIA Open was comprised of Kahuku, Mililani, Campbell, Kapolei, Moanalua and Waianae. Since then, Waianae and Moanalua have shifted to Division I while Farrington and Waipahu moved up to Open.

OIA D-I is comprised of Aiea, Kailua, Leilehua, Moanalua, Nanakuli, Pearl City, Radford, Waianae. Pearl City moved up from D-II.

Castle moved over from D-I to D-II, joining Kaimuki, Kaiser, Kalaheo, Kalani, McKinley, Roosevelt and Waialua.