CHICAGO – The search is over for general manager Ken Williams and the White Sox.

Desperate for stability and a proven bat, Williams didn’t wait for the trade market to heat up. Instead, the Sox became the aggressors Sunday by trading utility man Brent Lillibridge and right-hander Zach Stewart to the Boston Red Sox for third baseman Kevin Youkilis.

They also received cash considerations from Boston and will pay only $2.4 million of $8 million Youkilis is owed.

A walk-off win in extra innings, recapturing first place in the American League Central and an upgrade at third base capped the potentially season-changing day.

“I think at this point and time we owe it to our fans and the men in that clubhouse in uniform to try to exhaust ourselves to be the best team we could possibly be,” Williams said. “I don’t know if that means, often times that is, it’s determined by people that that means bringing veterans into the equation.”

Youkilis, 33, certainly brings impressive credentials to the South Side. As a three-time American League All-Star, Youkilis is a career .286 hitter with 133 home runs and 563 RBIs during his nine seasons with Boston.

Youkilis will join the Sox in Minnesota for their three-game series that begins tonight. Manager Robin Ventura said he doesn’t know where he’ll bat in the lineup and will figure it out in Minnesota.

The Sox hope the change of scenery helps Youkilis turn around his season. He was hitting .233 for the Red Sox with four homers and 14 RBIs.

“Just a gritty kind of player, and we’re happy to have him,” captain Paul Konerko said of Youkilis. “I think it could be a real steal when we look back on it.”

The trade does carry some risk for the Sox. Youkilis spent May 2 through 21 on the disabled list with lower back tightness and he has missed 30 games this season because of injury. He hasn’t played more than 120 games in a season since 2009. Considering his durability and injury issues, Williams and the Sox inquired about his health and were told by Youkilis “he hasn’t felt this good physically in a long time.”

“He’s very excited to join our club,” Williams said. “He has a little edge to him, which I like. I think he’s going to fit in just fine with our ball club.

“I can’t tell you exactly what he said, but he wants to come in and he wants to prove some people wrong.”

Williams commended Orlando Hudson’s effort at third base and the time he devoted to learning the new position with the Sox in a bind. Ultimately, Hudson did not improve the team’s production at third base – he is hitting .170 with a .247 on-base percentage – and few internal options forced Williams to look elsewhere.

The Sox’s third basemen, which include Brent Morel, Eduardo Escobar, Hudson and Lillibridge, combined to hit a position-worst .167.

“[Hudson] came in admirably and really went after it; he’s made some great plays over there,” Williams said. “In terms of wanting and needing a little bit more stability at the position, as well as providing a little bit of offense in the form that Kevin can provide it, another on-base percentage guy, another guy that is not afraid to get a big hit, we just thought at this time it was necessary and necessary to do it sooner rather than later.”

Hudson, who signed with the Sox on May 22 after the Padres released him, understood the organization’s decision to pursue a potentially more reliable bat. Ventura expects Hudson will join Escobar as a utility infielder.

“If I was a GM, I’d make the same trade,” Hudson said. “I’m not the best third baseman over there, plus I’m not swinging the bat well, so definitely, I’d make the same trade.”

Acquiring Youkilis raises concerns about the ailing Morel. Back problems have plagued the 25-year-old third baseman all season and the Sox finally placed him on the 15-day disabled list May 22. Morel wasn’t lighting it up in the 35 games before his DL stint, hitting .177 with no homers and five RBIs while posting a .225 on-base percentage. However, Morel had been pegged as the Sox’s third baseman of the future and provided outstanding defense.

Asked about the trade’s impact on Morel, Williams didn’t sound optimistic that he’d return to the field any time soon.

“Well Brent, all he can do right now is focus on his health,” Williams said. “We are focused on getting him the best possible medical care that we can give him and get him back on the field so right now, he’s not really a factor in terms of the major league team. We got to get him healthy so he can get back on the field No. 1.”

The Sox shouldn’t have too much trouble replacing Stewart or Lillibridge. Stewart, acquired in a trade with Toronto in July, went 3-7 with a 6.14 ERA in 28 games (nine starts) with the Sox.

Lillibridge, who earned the super utility man label for his ability to play seven different positions, leaves the Sox after four years. He hit .217 with 15 homers, 50 RBIs and numerous highlight-reel catches. Konerko called Lillibridge a great person that will be missed on and off the field.

“It’s part of the business,” Lillibridge said. “You never expect that’s going to be you in a trade like that. I’m excited. At the same time I love playing here. I enjoyed it so much, the guys here and the fans. I’m going to miss this place a lot.

“I’m excited though to see personally where my career will go and to help the Red Sox. But it’s tough.”