Molina going - it's Posey's time

He has exactly six starts as a big-league catcher, two this year. He appeared somewhat overmatched behind the plate in September. His experience with Tim Lincecum and Matt Cain, the Giants' two best starting pitchers, is limited.

Nevertheless, it's time for the baseball world to get more familiar with Gerald Demp "Buster" Posey.

When the Giants agreed to trade Bengie Molina, their starting catcher for 3 1/2 seasons, to the Texas Rangers on Wednesday, the message was twofold: Molina's numbers are down, and Posey's stock is up.

The Giants are getting reliever Chris Ray and a player to be named later. As of late Wednesday night, the Giants weren't saying it was official, apparently awaiting approval from the commissioner's office.

With Wednesday's 8-2 loss to the Dodgers, the Giants have dropped seven of eight. Their offense remains a mess (nine runs in their last five games), and Molina, who turns 36 this month, was hitting .257 with three homers and 17 RBIs.

Nothing like his contributions from 2007 to 2009, when he hit .278, averaged 18 homers and 85 RBIs, caught a two-time Cy Young Award winner (Lincecum) and twice won the Willie Mac Award as the Giants' most inspirational player.

Management repeatedly suggested Posey would get more playing time, and now it's a reality. However, Posey is in his own slump. He singled in his final at-bat Wednesday, but he had struck out in his first three at-bats to make him 0-for-13. In his last 14 games, he's hitting .146. He hit .429 in his first 13 games.

Eli Whiteside figures to remain in the mix at least as Jonathan Sanchez's personal catcher, though the two weren't at their best Wednesday, when the Dodgers completed their first three-game sweep in San Francisco since July 2007.

Sanchez surrendered four earned runs (and homers to Rafael Furcal and Matt Kemp) in five innings, and Whiteside was charged with a passed ball in the seventh, enabling Vicente Padilla to reach base on strike three during a three-run rally.

Sanchez also gave up an unearned run, thanks to left fielder Pat Burrell misplaying Kemp's third-inning single, helping the Dodgers take a 2-0 lead.

"We just got our tails kicked," manager Bruce Bochy said of a series to forget.

"Embarrassing," added Aubrey Huff.

The Giants flew to Colorado, and Molina was on the flight. By the time he landed, he was told of the pending trade to the first-place Rangers, who were seeking an experienced catcher to play ahead of Matt Treanor. The teams were in discussions on how to divvy up the remainder of Molina's $4.5 million salary.

Ray, 28, is 2-0 with a 3.41 ERA in 35 relief outings. He earned 49 saves for Baltimore in 2006-07 and missed 2008 because of Tommy John surgery. He went to Texas in the December trade that sent Kevin Millwood to the Orioles.

E-mail John Shea at jshea@sfchronicle.com.

This article appeared on page B - 1 of the San Francisco Chronicle