SAN FRANCISCO -- Justin Christian was back at the top of the Giants' lineup on Friday, and the 32-year-old outfielder may have impressed manager Bruce Bochy enough in the team's road trip to end the first half to become a more available option off the bench down the stretch.

The sparingly used Christian went 4-for-7 in two starts against the Nationals and Pirates before the All-Star break, scoring four runs and stealing a base. He got the start in right field and at the leadoff spot in Friday's game against the Astros.

"I liked what I saw," Bochy said. "I thought he threw out some great at-bats. He drove the ball, even when the right-handers got in there he had some quality at-bats, which was impressive considering the time that he missed. He kept his timing, and that's a credit to how hard he worked during all the games he had off. I think he's earned this."

The Giants faced left-hander Wandy Rodriguez, and the right-handed-hitting Christian got the nod over regular right fielder Gregor Blanco, who bats left-handed.

Bochy said he doesn't anticipate Christian will challenge Blanco for his spot despite Blanco's recent slump. Blanco has batted .220 in June and July after hitting .315 in May.

"We'll see. This is a lineup that has been pretty set, and we'd like to keep it that way as much as we can," Bochy said. "But again, because of the job he did on the last road trip, I wanted to give him the start against this lefty.

Christian's emergence gives Bochy another speedy player to plug into the leadoff spot, along with center fielder Angel Pagan.

"It would be nice to have another guy who can assume that leadoff spot when Blanco's not in there," Bochy said. "And Pagan, I wouldn't be surprised to see him lead off at some point occasionally in the second half as we give guys a break and mix it up a little bit. With Christian, it's nice to have someone like him. He really gives us three pretty good leadoff hitters."

Casilla's blister more of an issue than he let on

SAN FRANCISCO -- Giants manager Bruce Bochy said before Friday's game against the Astros that Santiago Casilla's blister on his middle finger has continued to improve, but it had affected the closer's command more than he had initially let on.

"I don't think as much as pitch selection as pitch location there," Bochy said. "It's such a fine line when you're making a quality pitch that if you have a little something going on with your finger, especially your [middle] finger, which plays a major role in your delivery and command, that'll play a part in you missing some spots."

Casilla last pitched on July 5 when an error-filled ninth inning led to his fourth blown save of the season in the Giants' 6-5 loss to the Nationals. Three of Casilla's four blown saves have come in his last four appearances.

"He's been so good, and he's going to have his hiccup every now and then, and he did," Bochy said. "I don't know what closer hasn't. If you look at his numbers and the [other] guys closing the game, we're pretty good."

Zito, then Vogelsong, to round out rotation order

SAN FRANCISCO -- The Giants' rotation will take on a new order in the second half, with Madison Bumgarner, Tim Lincecum and Matt Cain pitching in that order against the Astros, and Barry Zito and Ryan Vogelsong following to start the next series against the Braves.

The Giants had announced the three starters for the Astros before the break, and manager Bruce Bochy confirmed during Thursday's team workout that the lefty Zito will pitch ahead of Vogelsong so that there wouldn't another another left-hander right in front of the lefty Bumgarner.

"It's just breaking up the lefties," Bochy said. "We talked to them all, they're all good, and that's the plan coming out of the break here."

Bochy also didn't dismiss reports that he and general manager Brian Sabean will consider skipping Lincecum's spot in the rotation if he struggles again on Saturday.

"I don't want to put added pressure on him, but sometimes you have to do what's right," Bochy said. "I said this at Pittsburgh, but I think Timmy's going to bounce back and have a better second half. We certainly need him."

Lincecum's 6.42 ERA was the highest among qualified pitchers in the first half, and lasted 3 1/3 innings in both of his July starts before the break, giving up a combined 13 earned runs for a 17.55 ERA.