LOS ANGELES >> In the three months between spring practice and the start of training camp, Sam Darnold worked out with Jordan Palmer, his private quarterbacks coach in Orange County, to sharpen his throwing mechanics.

One adjustment centered on his delivery.

Darnold, USC’s third-year sophomore quarterback, aimed to shorten his throwing motion. At times, he felt it too closely resembled a baseball pitcher’s windup, where he made a loopy motion before firing a pass.

With the help of Palmer, a former NFL passer and the younger brother of Carson Palmer, Darnold sought to make his loop a little smaller.

Through more than two weeks of camp, Darnold thinks some of the offseason tweaks, however seemingly small, have helped.

“I see all the improvements,” Darnold said. “They’re showing up in the film room.”

He said the most noticeable difference has come on his deeper throws. In those situations, he has been less likely to start a long windup.

“Long balls, I have the tendency to drop the ball down a little lower, because subconsciously I’m like, ‘I have to get it down the field, so I have to put all my body into it,’” Darnold said, evoking images of a javelin thrower. “But that’s not the case. I just need to bring my hip through a lot more and stay the same up top.”

Darnold does not work out with Palmer in-season, setting aside any mechanical tweaks.

Asked if had noticed any changes with Darnold’s throwing motion, USC coach Clay Helton said he thought the quarterback was firing passes quicker.

Part of Darnold’s rationale for tightening his throwing motion was not only to relieve stress on his right arm, hoping it will serve as a preventive measure against injuries later in his career, but it might also help him develop more consistent, accurate velocity on his passes. In short: Rely less on his arm for strength, more on his core.

“With a stronger core than I had last year, I’m able to get the ball downfield a lot harder,” Darnold said.

In high school, Darnold started spending time with Palmer, who lives in Dana Point, near his family’s home in Capistrano Beach.

As Darnold has worked on his mechanics, Helton encouraged him not to change too much.

“The one thing we did talk about was remember that your creativity is part of your strength,” Helton said. “In real football, there are so many different arm angles that you have to have. Sometimes you can’t step into your throw. It’s just as important to work in all the adverse conditions and be used to that, because that’s real ball, than working pure mechanics.”

Earlier this summer, Palmer said he wanted Darnold to avoid dwelling on his mechanics once training camp began, a sentiment Helton echoed Monday.

“The game is played by not thinking, by being able to identify, and react, and believe in your fundamentals, and just habitual muscle memory,” Helton said. “So, I don’t like quarterbacks to overthink things. They got so much to worry about already. God gave you a specific skill set. You’ve honed in on it very well during the offseason. Now let’s go play.”