SAN FRANCISCO — The Giants are letting little mistakes and careless errors creep into their game — the very details that catcher Mike Matheny pays strict attention to getting right.

"He is being missed here," Giants manager Felipe Alou said. "I can't wait till he's in uniform on the bench, even if he's not playing. We miss that presence — that uncompromising, challenging presence. He is an in-your-face type of guy."

Matheny wasn't there to challenge teammates when the Giants held a players-only meeting to clear the air Tuesday afternoon. It lasted more than a half-hour.

Matheny remains at home in suburban St. Louis, and probably won't rejoin the team until the end of the month when the Giants travel to Pittsburgh on July 28-30.

Giants trainer Stan Conte plans for Matheny to see University of Pittsburgh head trauma specialist Dr. Michael Collins for another examination soon.

"The worst-case scenario is to get him in Pittsburgh when we are there so I can attend the appointment," Conte said. "I hope we can send him there earlier. But even if things aren't perfect, that's a good time for an evaluation."

Matheny continues to improve, though his post-concussion symptoms haven't cleared completely. It remains unclear whether he will play again this season, or resume his career at all.

"He's a four-time Gold Glove winner. Of course he's missed," right-hander Matt Morris said. "He brings a whole dimension to the defense, and we definitely miss his leadership."

TRADE CHATTER: Pirates first baseman Sean Casey told reporters that contract talks have not begun on an extension, increasing the chances that Pittsburgh GM Dave Littlefield will look to trade the popular player.

Casey remains the Giants' top trade target, and it's possible the club will seek to acquire left-hander Mike Gonzalez as part of a larger package. Both the Giants and Dodgers are interested in Gonzalez, according to an ESPN report.

Another first base option could be Javy Lopez, who is telling friends that he wants out of Baltimore at all costs. Lopez could play first base and serve as a backup catcher.

WORRELL GATHERS DUST: Even though the Giants are looking to acquire a setup reliever, Tim Worrell hasn't given up on pitching again this season.

Worrell has not picked up a baseball since June 27 because of one herniated disc and another bulging disc in his neck. Surgery hasn't been discussed yet, and the Giants seem content to let Worrell gather dust — even though he signed a two-year contract over the winter.

"I don't know what to do," Worrell said. "I'm kind of at a loss, other than I know I'm not right and there's stuff (in the tests) that shows I'm not right."

ONE-HOPPERS: Moises Alou didn't start, but not because of any medical reason. It was simply his day to sit in the four-man outfield rotation. ... Infielder Mike Cervenak went 4-for-4 Monday night and was batting .370 since rejoining Triple-A Fresno following a stint in the Korean League.