Contreras, pitching in front of representatives from at least six teams that included Florida, hurled seven shutout innings as the Sox held on for a 1-0 victory at Cleveland.
The Sox victory mirrored their formula for much of the first halfstrong starting pitching and enough offenseas they snapped a three-game losing streak while extending their lead in the American League Central to 10 games over Minnesota.
The Sox's lone run came in the first when Frank Thomas' drive grazed the glove of left fielder Coco Crisp for a double that scored Tadahito Iguchi.
The Sox (58-29) improved their major-league-best road record to 28-14 while beating the Indians in a one-run game for the sixth time this season.
The biggest lift came from Contreras, whose season has been marked by inconsistency. Contreras (5-5) backed up his vow last week that he is a better second-half pitcher.
"The rumors came in the first half because the numbers that were there were not numbers that pitchers have on a winning team," said Contreras, who lowered his ERA to 3.99 while winning consecutive starts for the first time this season.
"I wasn't throwing like I wanted."
But Contreras has allowed only two earned runs in his last 13 innings. He admitted he benefited from throwing on seven days' rest while improving his career record to 5-1 with a 2.47 ERA on six or more days of rest.
He also eased some concerns about the quality of the Sox pitching staff with scouts watching closely.
"Right now, we don't have anything in mind," manager Ozzie Guillen said. "We have every [scout] out there.
Guillen had a meeting after a mandatory one-hour workout five hours before Thursday's game to reinforce his faith in his team.
"I'm happy with what we have," Guillen said. "If we need some help, I bet you [general manager] Kenny Williams will get some help."
For the second time in as many Sox series, a Florida representative was in attendance.
This time it was Dan Jennings, the Marlins' vice president of player personnel.
The two sides, however, gave themselves flexibility on their 40-man rosters with the July 31 non-waiver trading deadline approaching.
Left-handed reliever Kevin Walker was outrighted to Triple-A Charlotte on Wednesday, three days after the Sox optioned him.
The Marlins, meanwhile, designated veteran left-hander Al Leiter for assignment.
Florida's Burnett also falls under scrutiny, although the Marlins have a shortage of starting pitching.
Burnett, who threw a no-hitter in 2001 but is two years removed from reconstructive right elbow surgery, was tagged for six runs in five innings Thursday in a loss at Philadelphia.
Contreras, meanwhile, looked dominant with a split-finger fastball to complement his fastball.
"If [Contreras] throws the way he throws the last two [times], watch out," Guillen said. "He has a chance to be outstanding.
"But he's also got a chance to be very bad. I was very impressed."
Left-handed reliever Damaso Marte was just as dominating as he struck out all three batters he faced in his first outing since coming off the disabled list.
"Everyone knows that pitching is what we're built around," catcher A.J. Pierzynski said. "Defense, and scoring just enough runs."