Kansas City, Mo. ? Ken Williams spotted Ken Griffey Jr. in the White Sox’s dugout and smiled.

“Welcome to the family,” the general manager said, hugging his new center fielder.

One of Griffey’s family chores will be tracking down fly balls. There is no point in tiptoeing around the issue. Can a 38-year-old future Hall of Famer with a lengthy history of injuries play center field decently enough to help a team win a pennant?

Where, pray tell, is Junior’s confidence level when it comes to roaming wide-open spaces?

“I’ll let you know better after the game,” he said before his Sox debut Friday night.

So?

“It was fine,” he said after the Sox’s 4-2 victory over the Royals. “When you only have three balls hit to you, you don’t have to do too much moving.”

Some of you probably think that worrying about the state of Griffey’s defensive skills is missing the point, like worrying about Hemingway’s penmanship. Jeez, he had two RBI singles Friday.

But it does matter. Baseball might be in danger of being taken over by stat freaks, but defense is important, as hard to quantify as it sometimes is.

It’s not just a doubting columnist who wonders about Griffey’s ability to play center field. He was concerned enough about it that he reportedly considered blocking the trade from Cincinnati. He didn’t want to embarrass himself or hurt the Sox.

But Williams made it clear to him in a telephone conversation before the Thursday trade that the Sox would be very flexible.

“Like I explained to him, he only has to go out there when he feels good and good enough to where he feels like he can give us a chance to win with him being out there,” Williams said. “But if he doesn’t feel like his body is going to allow that on a particular day, all he’s got to do is go to Ozzie (Guillen).”

As long as Griffey can handle center field, this is a win-win situation for the Sox. It’s not as if Nick Swisher has been channeling Willie Mays. The Sox haven’t been the same at the position since they dealt Aaron Rowand to Philadelphia in the Jim Thome trade after the 2005 season.

But they need Griffey at least to be serviceable in center to benefit from the hitting they’re counting on from him. He had been playing right field for the Reds the last two seasons. His legs have been through a lot, which might be good for someone in a frequent-flier program but not for someone who has to play center.

“I think he wanted me to know, in case I didn’t know, not to expect what we were used to seeing out there,” Williams said. “That’s the reason I said you only play when you feel great. When you don’t feel great or don’t feel healthy, that’s OK. We have plenty of options.

“I told him that it’s not as if he’s replacing the prototypical guy that was already out there.”

The idea is that Carlos Quentin, Jermaine Dye, Paul Konerko, Thome and Swisher all will be fresher down the line, thanks to the addition of Griffey.

Guillen said he doesn’t want Sox fans to look at Griffey as a savior, and anyone of sound mind would agree that no walking on water is expected.

But running on grass is demanded. Guillen said playing center field is like riding a bicycle. Perhaps. When you’re 38, it can feel as if you’re on a tandem solo.