Sam Darnold keeps quarterback battle tight in USC’s first scrimmage

The managers manning USC’s yardage markers were atwitter on Wednesday. Sam Darnold darted passes across the field, mostly safe and short: ins, outs, screens and check-downs. The chains kept moving.

On one play, Darnold eluded a heavy pass rush by scrambling to his right, then uncorked a pass, on the run, to De’Quan Hampton, who was blanketed in coverage. The pass shook Hampton loose. He caught it for Darnold’s longest completion of the day.

The first eight passes Darnold threw Wednesday ended like this, nestled into a receiver’s arms. A shaky middle portion dented his total slightly, to 15 completions in 22 attempts with a touchdown. He also ran for a score and had a fumble.

USC Coach Clay Helton plans to decide between Darnold and Max Browne to start at quarterback on Aug. 20. So far, six practices in training camp have provided little clarity.

Helton declined to evaluate which passer performed better, but Darnold appeared to have the better scrimmage Wednesday after an uneven start to training camp.

“Sam is getting a little bit more consistent,” Helton said. “I thought in a couple of the early practices he showed a little bit of, you know, redshirt freshman. And then all of a sudden practice three and four were outstanding.”

Browne, Helton said, “has been pretty consistent” throughout camp. The staff has been encouraging him to take more shots.

He did on Monday, at the Coliseum, where he lofted a long touchdown pass down the seam. He did again Wednesday, though with few connections. One long pass, in the face of a blitz, was catchable, but went to the receiver’s wrong shoulder. A well-placed fade in the end zone wasn’t completed and another would-be touchdown was thrown slightly high and dropped.

On Wednesday, Darnold played more efficiently and Browne more aggressively. Browne completed 10 of 21 passes with one interception.

Passing statistics in scrimmages, when coaches try to evaluate players in different situations, aren’t perfectly analogous to games. Still, Darnold’s day showed there remains little separation, though each quarterback could play better.

“I don’t think they were perfect today, just to be honest with you,” Helton said.

He paused.

“By far not perfect,” he said.

USC freshman running back Vavae Malepeai carries the ball to the lift during the first day of fall camp at Howard Jones Field on Aug. 5.

(Shotgun Spratling / Los Angeles Times)

Malepeai breaks shoulder

Vavae Malepeai walked onto the practice field Wednesday with his arm in a sling. The freshman running back had broken his shoulder blade, Helton said. He is expected to miss six to eight weeks.

Malepeai was unlikely to become an impact player in his first season, with Justin Davis and Ronald Jones II consuming most of the carries. But Malepeai had sparked excitement.

His scapula fracture is the first training-camp injury expected to extend into the regular season. Malepeai will not require surgery, Helton said, and could return around the second to fourth week of the season.

Quick hits

The MRI exam on defensive tackle Noah Jefferson’s injured back “came back clean,” Helton said. Jefferson will see a specialist, and USC hopes to have him back for the second half of training camp. … Defensive tackle Khaliel Rodgers (concussion protocol), offensive tackle Chad Wheeler (foot) and receiver Jalen Greene (hamstring) returned to practice Wednesday. … Running backs James Toland IV and Chris Edmondson had groin injuries. … Offensive lineman Chuma Edoga injured a toe and was pulled from practice. … Kicker Michael Brown (quadriceps) and Marvell Tell III (hamstring) did not practice. ... Matt Boermeester made eight of nine field-goal attempts, including one end-of-game situational kick from about 45 yards and another from about 45 to 50 yards.

zach.helfand@latimes.com

Twitter: @zhelfand