CHICAGO —Hunter Pence continues to make hard contact with his new hitting approach at Triple-A Sacramento, and fellow Giants outfielder Mac Williamson gave a glowing review.

“We talked a lot while I was there,” said Williamson, who returned from the disabled list Friday after playing five rehab games for the River Cats. “He’s making some good strikes. He’s got the basic concepts down.

“Look, he had a crash course in the middle of the season. Anybody can admire what he’s done in the middle of a season and trying to make it work while playing games.”

Pence, in the minors on a rehab stint after injuring his thumb, is hitting .321 at Sacramento. His success comes after working with independent hitting instructor Doug Latta, who helped re-create Williamson’s swing in the offseason — upright stance, lower hands, aggressive leg kick.

“I was there for a month and still didn’t think I had it down pat,” Williamson said of his time with Latta.

Mac’s concussion: In his first interview since his April 24 concussion, Williamson said he felt extremely nauseated and dizzy at times.

“I never had one before,” he said. “I didn’t really know what I was feeling or wasn’t feeling. Some days I was feeling really good, and then I took the exertion test and felt awful after that.”

Santiago Mejia/The Chronicle

A visit with concussion specialist Dr. Micky Collins in Pittsburgh was a turning point.

“I felt a lot better coming out of that meeting and had a better idea,” Williamson said. “Half the battle is really not knowing what’s going on. You’re left in dark a little bit. It is scary. It all started to come together, and I’m happy to be back.”

Asked if he’ll be extra careful of the AT&T Park bullpen mounds, where Williamson tripped and got concussed, he said, “I’ll be extra cognizant of them. The tough thing about it for me was, I felt I didn’t really do anything stupid. It wasn’t a stupid try-hard play where I dove onto the mounds or slid into the mounds. Can you imagine if I would’ve pulled up and just let that ball fall and not given an attempt? I think it would’ve been a quick ticket back to Sac.”

Briefly: To create roster space for Williamson, reliever Josh Osich was optioned to Sacramento. The Giants are considering adding a reliever for the upcoming series in Denver. ... Shortstop Brandon Crawford made another flashy play, bare-handing Javier Baez’s fourth-inning grounder (which ricocheted off third baseman Evan Longoria’s glove) and throwing a one-hopper to Brandon Belt, who scooped it. “He probably made the best play of anybody,” Crawford said. “I’m trying to help Belt get a Gold Glove.”

John Shea is The San Francisco Chronicle’s national baseball writer.