CINCINNATI - Ken Griffey Jr. is leaving home to get back in a pennant race.

The Chicago White Sox acquired Griffey from the Cincinnati Reds on Thursday, hoping the 38-year-old outfielder can help them hold onto their slim lead in the AL Central.

The Reds sent Griffey and cash to Chicago for reliever Nick Masset and Triple-A second baseman Danny Richar. The deal was announced a half-hour before the 4 p.m. EDT deadline to make trades without waivers.

Griffey, who hit his 600th home run this season, agreed to the trade earlier in the day. Because of the cash transaction involved, the deal did not become official until the commissioner’s office approved it.

White Sox general manager Kenny Williams coveted Griffey for several years. Once one of baseball’s premier players, Griffey has never reached the World Series and has not even been in the playoffs since 1997 with Seattle.

“One of the things that factored into this was a guy who has had a great career but has not won a championship and how motivated he’s going to be to get on that stage,” Williams said. “That is a factor and will always be a factor for me.”

Now older, it’s uncertain how much Griffey has left in his oft-injured body — it’s been a long while since he was voted to the All-Century team.

Griffey played right field the last two seasons, but will return to center when he joins the White Sox on Friday for the start of a series in Kansas City. Manager Ozzie Guillen and the White Sox led Minnesota by 1½ games when the trade was made.

“When I talked to Junior, he was very honest,” Williams said. “He said, ’Well, I’ve got to tell you, I don’t know that you’re going to see the guy from Seattle.’ I said, ’We’re not looking for that guy from Seattle. What we’re looking for is for you to use your instincts.”’

Griffey takes over for Nick Swisher, who moves to first base in place of the slumping Paul Konerko. Swisher also will give up his No. 30 to Griffey, who wore it during his earliest years in Cincinnati.

“I just think there’s a lot of added things he can bring,” Swisher said. “I mean, I had posters of that guy on my wall growing up. So I think it’s going to be an awesome thing for all of us.”

Reds general manager Walt Jocketty was surprised when the White Sox approached him on Wednesday. Griffey also was caught off-guard.

“I think he was just a little bit surprised, maybe, but I think he thought about it and said he wanted to talk to his family about it,” Jocketty said. “I think he agreed it’s a very good opportunity for him, and the club obviously wanted him and pursued him and came after him. That’s got to be a good feeling for him, I guess.”

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The trade ended a bittersweet stay with his hometown team — a lot of injuries, a few benchmark homers, no playoff appearances.

Notably, his last hit with the Reds was a homer.

Griffey was on pace to break Hank Aaron’s home run record when he came to Cincinnati in a trade with Seattle before the 2000 season. A series of severe injuries dropped him well off the pace. He finally hit No. 600 this season — only the sixth player to reach the mark — but struggled mightily at the plate.

That short, sweet swing has slowed down this year.

Griffey hit a three-run homer in a 9-5 win at Houston on Wednesday that left him with 15 home runs, 53 RBIs and a .245 batting average despite playing in one of baseball’s most homer-friendly ballparks. His 608th homer left him one behind Sammy Sosa for fifth place on the career list.