STOCKTON — Jonah Heim has a knack for knowing what to say to pitchers when he visits the mound.

The Stockton Ports catcher, so says starter Brian Howard, may come prepared with strategy, a joke, or direct advice.

“Or he’ll say, ‘You’re not pitching well. Start pitching well,’” Howard said lightheartedly before Wednesday’s game against the San Jose Giants. “He’s got a good feel for what he needs to say.”

Heim has a good feel for the game, too, and is batting a team-high .297 among season-long starters.

He was resting Wednesday, for the second consecutive night after the Ports clinched a first-half title Monday, as Stockton shut out San Jose 6-0 in front of 2,423 at Stockton Ballpark.

“Jonah is the ultimate pitcher’s catcher. He knows what a pitcher needs and does a great job of calling the game,” said Howard, who came within one strike of throwing a complete-game shutout Tuesday. “We’ve become (good) friends throughout our time here, and that definitely helps.”

Heim, who turns 23 on June 27, is a 6-foot-4, 225-pound switch-hitter and fourth round MLB draft pick of the Baltimore Orioles. He’s delivered six homers, 18 doubles, 35 RBI, and a strong defensive presence in his short Stockton tenure.

“It’s hard to find a combination in a catcher who offers both the defensive and offensive potential. He certainly brings that to the table,” Stockton manager Rick Magnante said.

Heim has done his best to mesh with Stockton’s pitching staff since arriving in spring training, and it’s worked. The Ports (42-24) are North Division first half champs, guaranteeing a playoff berth in September.

“It’s always different getting traded and coming to a new team,” said Heim, who’s been with the Orioles, A’s and Tampa Bay Rays organizations. “You’ve just got to get some camaraderie with the guys and get to know them.

“It’s huge, just sitting in the locker room talking … getting to know them at a personal level.”

Heim has never been above advanced-A ball (which is the Cal League’s level), but Magnante foresees a strong future.

“You’re looking at a switch-hitting catcher who’s got a fundamentally-sound set-up at the plate, a good physical approach that allows him to recognize pitches, a swing that works well in the zone,” Magnante said.

“And he’s a young guy who really hasn’t reached manhood quite yet either (physically).”

Heim also caught for two tremendous pitchers in the first half.

Both starter Parker Dunshee and closer Miguel Romero were promoted to double-A Midland, Texas, on Wednesday. Upon his departure, Dunshee was fourth in the Cal League with a 2.70 ERA. Romero, a native of Cuba, had posted a Cal League-best 13 saves with 33 strikeouts to four walks.

“Both of them really deserved the promotion, and they got it, so that’s great for them. I’m proud of them,” Howard said.

“We’re going to continue to do the little things right here. Hopefully we won’t miss a beat with those two guys leaving.”

Big-time performances

Heim’s fill-in, catcher Jason Goldstein, launched a grand slam to left-center field in the fifth to break the game open. It was Goldstein’s first homer of the season.

Stockton starter Matt Milburn earned the win with a quality start on Wednesday, throwing seven scoreless innings, allowing five hits and striking out six with no walks.

Brusa, Theroux return

University of the Pacific’s Gio Brusa, the Giants’ first baseman and No. 3 hitter, and Delta College’s Collin Theroux, the Ports’ designated hitter and No. 9 hitter, were both in the lineup Wednesday.

Brusa, a St. Mary’s High graduate from Lodi, was 0 for 3 with a walk. Theroux was 1 for 2 with two walks and a run scored.

It’s been an odd series for Brusa. Brusa popped out to end the game on Monday as the Ports clinched their crown, but the next day, hit a solo homer in the ninth to nix Howard’s shutout.

The Giants fell to 32-34 on Wednesday.

A’s rehab

Oakland’s Boog Powell made another appearance with the Ports, leading off and playing left field. He lined out to center field in the first, walked in his subsequent two at-bats and grounded into an inning-ending double play in the fifth.

Powell scored a run in the third on Nate Mondou’s hard-hit single to center field.