PASADENA — The UCLA football team’s Week 2 game against FCS school Alabama State was a bit of a head-scratcher from the start Saturday.

Bruins star running back Zach Charbonnet did not play despite being dressed, quarterback Dorian Thompson-Robinson was knocked out of the game less than three minutes into the second quarter and a host of reserves played significant early snaps.

Backup quarterback Ethan Garbers ran for two of UCLA’s five rushing touchdowns and the defense posted a second-half shut out for a second consecutive week in a 45-7 win. The Bruins (2-0) led by 24 points at the half and emptied most of the bench by the third quarter.

The early story was the absence of Charbonnet, who was walking around the team bench but did not see the field in the first 15 minutes. Afterward, UCLA head coach Chip Kelly would only say he was “unavailable” but alluded to the decision being in the hands of the training staff for the following week.

“We’ll just take it as it comes. I don’t make those decisions,” Kelly said.

In his place, backup Keegan Jones punched in the Bruins’ first score on a 2-yard run to take the early lead midway through the quarter.

The Hornets, who typically employ a two-quarterback system, were without Dematrius Davis. He was a game-time decision earlier in the week.

Myles Crawley got the start and enjoyed early success, completing eight of his first 11 throws. UCLA linebacker Laiatu Latu put an end to that before Crawley could get off a 12th throw, forcing a fumble at the Alabama State 20-yard line that teammate Gabriel Murphy scooped up.

After a flag on the fumble return, the Bruins pushed the lead to 14-0 on the first play from scrimmage. Thompson-Robinson found tight end Hudson Habermehl open over the middle for the 25-yard score with 4:53 left in the quarter.

“We work that play a lot,” said Habermehl, who started in place of the injured Michael Ezeike. “I saw a cover-zero blitz. We repped it a lot during practice. Caught it and it was just instinctual from there.”

The Bruins had early issues with the pass defense, including a 21-yard connection from Crawley to wide receiver Jeremiah Hixson to cut the deficit to 14-7.

For the game, UCLA allowed 223 of its 310 yards through the air but collected six tackles for loss, including three sacks.

Less than three minutes into the second quarter, Thompson-Robinson appeared to hurt his ankle on an 18-yard shovel pass to Jones. After a 12-yard completion to Jake Bobo on the next play, Thompson-Robinson was replaced by Garbers and did not return.

Thompson-Robinson completed 9 of 11 passes for 101 yards before exiting.

Both of Garbers’ touchdown runs came in the second quarter, extending the Bruins’ lead to 31-7 going into the break.

Through the air, Garbers finished 14 of 18 for 164 yards and an interception.

In the third quarter, third-string UCLA running back TJ Harden tacked on a 13-yard touchdown run for his first collegiate score to push the advantage to 38-7.

Harden finished with a game-high 56 yards on seven carries.

Christian Grubb’s 7-yard touchdown run in the fourth capped the scoring.

1st quarter

7:58, UCLA: RB Keegan Jones 2-yard TD run (PAT GOOD, Nicholas Barr-Mira), 7-0 UCLA

4:53, UCLA: QB Dorian Thompson Robinson to TE Hudson Habermehl, 25-yard TD pass (PAT GOOD, Nicholas Barr-Mira), 14-0 UCLA

2nd quarter

Alabama State, 13:53: QB Myles Crawley to WR Jeremiah Hixson, 21-yard TD pass (PAT GOOD, Nathaniel Eichner), 14-7 UCLA

UCLA, 10:39: QB Ethan Garbers 5-yard TD run (PAT GOOD, Nicholas Barr-Mira), 21-7 UCLA

UCLA, 2:43: K Nicholas Barr-Mira converts 19-yard FG, 24-7 UCLA

UCLA, 1:02: QB Ethan Garbers 2-yard TD run (PAT GOOD, Nicholas Barr-Mira), 31-7 UCLA

3rd quarter

12:23, UCLA: RB TJ Harden 13-yard TD run (PAT GOOD, Nicholas Barr-Mira), 38-7 UCLA

4th quarter

13:24, UCLA: RB Christian Grubb 7-yard TD run (PAT GOOD, Joseph Firebaugh Jr.), 45-7 UCLA