Konerko gets in some swings

Despite being sidelined since mid-June with a strained left oblique muscle, White Sox first baseman Paul Konerko was one of the first players on the field taking batting practice before Thursday's game at U.S. Cellular Field against the Oakland Athletics.

Due to the extent of the injury, Konerko is headed to Class AAA Charlotte for a rehab assignment this weekend, but White Sox manager Ozzie Guillen said before the game he was pleased with what he saw in the batter's box.

"I don't see any problem," Guillen said. "I didn't hear any complaints when he left the cage ... you are either OK or not, but I love the way he swings the bat. I love his approach to the ball."

Familiar faces: Despite being on the disabled list with a sore right quad, former longtime White Sox player Frank Thomas made the trip to Chicago for the first time since rejoining the A's this year.

Thomas, who played with the White Sox for 16 seasons, is rehabbing at home in Las Vegas but said he had no plans on missing this road trip. Before the game, he was greeting current Sox players Nick Swisher, Jim Thome and Jermaine Dye during batting practice. Thomas has been on the DL since May 29.

"This is home," Thomas said of Chicago. "This is what made me who I am."

A's outfielder Ryan Sweeney also used to play for the White Sox. Sweeney made his big-league debut in Chicago in 2006 before being part of the trade that brought Swisher to the South Side in the off-season.

Sweeney, a native of Cedar Rapids, Iowa, was injured the last time the A's came to town in mid-April, so he was glad he got the chance to be in the lineup and play in front of his family and friends in the first game of the series.

"It's just another game," said the lefty Sweeney. "My parents came down last time, but it's better they see me in person playing."

Bullpen power: The White Sox lead the league in ERA at 3.38. The last time they finished on top in the American League was in 1994 (3.96).

The Sox have allowed 3 runs or less in 44 of their 84 games, including 5 shutouts and 13 games with 1 run given up.

"These guys are all about believing in themselves," Guillen said.