The Boise State basketball team opened the second half of its victory against Fresno State on Wednesday night with an unusual lineup.

For the Broncos, at least.

Instead of their typical four-guard alignment, the Broncos started with centers Ryan Watkins and Kenny Buckner on the floor.

With guard Jeff Elorriaga sidelined indefinitely with more concussion-like symptoms, the Watkins-Buckner combination could become the Broncos’ new normal.

“Kenny and Ryan have both been playing well. They’re both really good defenders, it gives you size and both of them are rebounding at a high level,” coach Leon Rice said. “So you’re probably adding a little bit defensively and a little bit on the boards and you’re probably subtracting a little bit with the way we shoot the ball and the way we can move the ball.”

Elorriaga suffered a concussion against New Mexico last week and missed the loss at Air Force. He returned Wednesday against Fresno State, but hit his head on the floor late in the first half. He did not play in the second half and has been ruled out for Saturday’s game at Nevada.

“He’ll be out for a while,” Rice said.

It is a costly loss for the Broncos. Elorriaga is among the top 3-point shooters in the nation at 48.3 percent. He is one of the team’s best defenders, smartest players and top leaders. He leads the team in minutes played per game (32.4). Teammates cited his absence as one of the reasons for their poor showing at Air Force.

“When he’s in the game, he puts more pressure on you in terms of having to play another shooter out there,” Fresno State coach Rodney Terry said. “He gives them a level of toughness, too. He’s a great glue guy for them. He makes everything flow.”

Rice said Elorriaga was cleared by doctors and trainers to play against Fresno State. Elorriaga, who played high school football, said he had never had a concussion before last week.

“It’s more about the way Jeff plays,” he said. “I can’t fathom him being out on the court without hitting the ground and taking charges and battling in there on the boards. That’s a tough combination when you have a head problem.”

The 6-foot-8 Watkins, who grabbed a career-high 18 rebounds against Fresno State, plays power forward when he and Buckner (6-9) are on the floor together. In the four-guard alignment, 6-6 wing Anthony Drmic has guarded opposing power forwards.

The Broncos have not practiced the two-big alignment lately, as Buckner missed three games because of a team suspension.

“We feel like we can get up to speed in a couple days of work,” Rice said. “There’s trade-offs. Our offense was one of the most efficient in the country with the four guards and Ryan. Our defense might get better and rebounding could still get better.”

Boise State (14-4, 2-2 Mountain West) leads the conference in scoring at 77.7 points per game.

Elorriaga’s absence will further test an already undermanned roster. The Broncos have been playing just seven players, including Elorriaga. Thomas Bropleh, the team’s eighth man, is battling a wrist injury and is questionable.

“You’ve got a guy that never comes out of the game and he’s out of the game,” Rice said. “It disrupts you.”

Brian Murphy: 377-6444, Twitter: @MurphsTurph