SAN FRANCISCO -- Andre Ethier was out of the Dodgers starting lineup Tuesday night, in part because he's struggled against left-handed pitchers and in part because of a right knee that could require offseason cleanup arthroscopy.

"It's just a day off," said manager Don Mattingly. "Dre's been battling lefties [.228] and I'm hearing a little more about his knee. It's a good day to give him."

Ethier hyperextended his right knee in Spring Training 2010 and ices it after every game. On an at-bat in Arizona over the weekend, he stumbled out of the batter's box on a swing. Nonetheless, he's played all but two games this year.

As for the pitching matchup, Ethier was 1-for-10 against Madison Bumgarner, San Francisco's starting pitcher Tuesday night. Mattingly said he expects Ethier to be in the lineup Wednesday, when the Dodgers face Tim Lincecum. Ethier is 9-for-32 with two homers against Lincecum.

"The same stuff he had last year," Mattingly said of Ethier's knee. "It comes and goes. He was ready. He was a little bit surprised."

Ethier is 1-for-16 since his All-Star appearance, his batting average slipping below .300 for the first time since the second game of the year.

"In Arizona, he gets frustrated because nothing was really falling," said Mattingly. "The last game there, he scalded one 410 feet and it's caught, hit a liner to left. He just gets frustrated when he doesn't get hits. He needs to stay in the strike zone. He has a tendency, when we're not scoring runs, to try to make something happen."

Juan Rivera replaced Ethier in right field.

Blake takes step forward with neck injury

SAN FRANCISCO -- Only days after fielding questions about retirement because his arthritic neck was not improving, Casey Blake's arthritic neck is improving.

Blake, limited to playing catch for the two weeks he's been on the disabled list, added fielding ground balls and soft-toss batting practice Tuesday.

"He said he woke up feeling better, and that's the first time I've heard that," said manager Don Mattingly. "He's got more movement. We'll add on and see how he handles it."

Blake, a possible free agent after the season, has been on the DL three times this year -- the other times for a strained lower back and a staph infection.

Dodgers, Thames officially part ways

SAN FRANCISCO -- Outfielder Marcus Thames cleared release waivers and has become a free agent.

The Dodgers signed Thames for $1 million to be the right-handed platoon left fielder with Jay Gibbons. But Thames was hampered by leg injuries and spent one month on the disabled list with a strained calf.

When he did play, it didn't work out. In 36 games he hit .197 with only two home runs and seven RBIs. He was designated for assignment July 12 to make room for Juan Rivera, who was acquired from Toronto. Rivera already has a home run in three games.

Gibbons, meanwhile, struggled with vision problems, had one homer and five RBIs while hitting .255 and was designated for assignment June 6 when Thames came off the disabled list.

Gibbons cleared waivers and was outrighted to Triple-A Albuquerque, continued to experience vision problems and underwent another corrective operation that seems to have resolved his problem. In his last five games with the Isotopes, Gibbons is hitting .438.