SAN FRANCISCO -- Edgar Renteria stood at his locker, shook his head and muttered, "Unbelievable."

It's been that kind of year for Renteria, who on Wednesday made his third trip of the season to the disabled list, this time with a strained left biceps.

Renteria originally aggravated his biceps swinging the bat in last weekend's series opener against Atlanta and missed the final three games. Renteria played Monday against the Cubs, but left Tuesday's game in the fifth inning.

Renteria said he hopes to return in two to three weeks.

"I'll just get treatment and get strong again and hope in September everything's fine," Renteria said.

Renteria missed nearly a full month of action earlier this year, when a right groin strain shelved him from May 7-22. Four days after his return, Renteria pulled his right hamstring and was on the DL until June 16.

Giants still talking with top Draft pick

SAN FRANCISCO -- Vice president of baseball operation Bobby Evans said negotiations with No. 24 overall pick Gary Brown and his agent, Scott Boras, are "ongoing" as Monday's signing deadline approaches.

"Everything from here on is deadline dealing," Evans said Tuesday at AT&T Park.

The Monday deadline is 9 p.m. PT.

The 21-year-old center fielder finished his junior season at Cal State Fullerton hitting .438 with eight triples, six home runs and 41 RBIs. He missed the end of the season with a broken middle finger on his left hand, only appearing in the Titans' final two games of the College World Series as a pinch-runner.

"He should be all healed up by now," Evans said of the finger. "We won't know until we get him signed and [examined]."

Worth noting

Buster Posey's seventh-inning double Monday was changed to an error on Cubs outfielder Tyler Colvin. Posey finished 2-for-5 with two RBIs instead of 3-for-5 with four RBIs. ... Infielder Eugenlo Velez, who was hit in the head by a foul ball July 25, was activated from the 15-day disabled list Wednesday and optioned to Triple-A Fresno. ... Left-handed reliever Dan Runzler (dislocated left patella) began a Minor League rehab assignment Wednesday for Rookie-level Arizona. He pitched two perfect innings, striking out four batters. ... Bochy said he expects left-hander Jeremy Affeldt (strained left oblique) to begin his rehab Friday for Class A San Jose. ... Wednesday was Pablo Sandoval's 24th birthday.