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Prior to taking on the Red Sox, the A's swept two games at the Tokyo Dome against the Nippon Baseball League's Yomiuri Giants and Hanshin Tigers.
"Getting to watch those games and see what it's going to be like, how the fans are going to react, I think that'll help me," Blanton said.
Geren is confident that Blanton, 27, will get plenty of help from his teammates, too.
"We've had a great spring, and we've carried the momentum over here," Geren said. "Hopefully we can carry that over against the Red Sox."
Of tabbing Blanton to kick things off, Geren said, "Starting on Opening Day is an honor, and Joe deserves it. He's been a rock in our rotation for a long time, and this is kind of a reward for that."
Blanton appreciated getting a heads-up on the early international assignment almost as much as he appreciates the honor.
"It was really nice to know exactly where I was slotted before we even got [to Phoenix]," he said before the team left for Japan on March 19. "Everyone's more comfortable when their routine's been established, and we had ours set even before Day 1."
Not that it changed Blanton's preparation much.
"I just made sure my arm was in good shape by the time I got down here," he said. "I threw one or two extra bullpens [in the offseason], but other than that, the only real difference has been in the first one or two starts this spring. Instead of going two innings the first time, I went three, and the buildup just started a little earlier.
"But I was ready for it. I feel like I'm right where I need to be."
For much of the offseason, it wasn't clear if Blanton, who went 14-10 with a 3.95 ERA in 34 starts last season, would even be with the A's this year.
Haren was traded to the Diamondbacks in an eight-player blockbuster that signaled the start of a youth movement for Oakland, and the movement included deals that sent outfielders Nick Swisher and Mark Kotsay to the White Sox and Braves, respectively, for more prospects.
Of the 11 players acquired in those three deals, seven were pitching prospects. Blanton's name had started surfacing in trade rumors before the 2007 deadline, and he was still thought by many to be on the block as recently as February.
"I knew it was going on," he admitted, "but you really can't think about it a lot. You'll drive yourself crazy. The way I looked at it was, 'I'm here until someone tells me I'm not, and no matter what happens, I'll be pitching for someone,' so I still had to just focus on pitching."
Now he has the difficult task of focusing on pitching in Japan against a Japanese hero, Boston's Daisuke Matsuzaka. But in typically understated fashion, Blanton downplayed the hype and turned it in his favor, saying the experience will help diminish any nerves he might battle when he again takes on Matsuzaka and the Red Sox in Oakland's home opener at McAfee Coliseum on April 1.
"Same team, same pitcher for the other team. The difference is that in Oakland, we'll have our crowd behind us," Blanton said. "Here in Japan, everyone's going to be going crazy for Dice-K and the Sox."
In essence, Blanton has two Opening Day starts, and he welcomes the challenge.
"That," said A's rookie lefty Dana Eveland, who started the exhibition opener here against Yomiuri, "is why he's our ace."
The A's will be without star third baseman Eric Chavez, who missed the trip and will start the season on the disabled list while continuing to rehab his surgically repaired lower back. But Oakland went 16-7 without Chavez during Cactus League play, and Chavez's replacement, Jack Hannahan, hit a monster home run to center field during the win over Yomiuri.
Outfielder/designated hitter Jack Cust, shortstop Bobby Crosby, outfielder Travis Buck and reserve infielder Donnie Murphy also homered here, Murphy's being a grand slam to ice a 10-2 victory over Hanshin.
"We've been playing the game real well, playing real hard," said Cust, who led the A's with 26 homers last season despite not joining the team until May. "If we can continue that in the regular season, we'll be all right."
Added Blanton: "I think we're ready. I really do."
BOS: RHP Daisuke Matsuzaka (15-12, 4.40 ERA in 2007)
Matsuzaka returns to his homeland to become just the second native of Japan to start a season opener. Hideo Nomo started the 2000 opener for Detroit and the 2003 and '04 openers for the Dodgers. Matsuzaka also becomes just the second pitcher ever to start a season opener in his home country outside the United States. Canadian Ryan Dempster started for the Marlins in Montreal on April 2, 2002.
OAK: RHP Joe Blanton (14-10, 3.95 ERA in 2007)
The right-hander gets his first start of the regular season after posting an 0-1 mark in four Cactus League starts for the A's. In 17 innings, he allowed 19 hits and nine earned runs for a 4.76 ERA. Blanton has recorded double figures in wins in each of his first three full seasons with Oakland, winning 12, 16 and 14, respectively, from 2005 through last season.
The A's will try to carry the momentum of a strong Cactus League over to the regular season. They finished the Arizona portion of their schedule with a 16-7 mark. Last season, they also finished above .500 at 17-12-2, but finished third in the American League West with a 76-86 mark. ... Emil Brown will wear No. 8 for the games in Japan while Lenny DiNardo will wear No. 25 and Dana Eveland will wear No. 35.
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Wednesday: Red Sox (Jon Lester, 4-0, 4.57) vs. A's (Rich Harden, 1-2, 2.45), 3:07 a.m. PT
Friday: A's (TBA) at Giants (TBA), 7:15 p.m. PT (Exhibition at AT&T Park)
Saturday: Giants (TBA) at A's (TBA), 12:35 p.m. PT (Exhibition at McAfee Coliseum)
Sunday: A's (TBA) at Giants (TBA), 12:35 p.m. PT (Exhibition at AT&T Park)