After making a major contribution for the reigning World Series champions in 2005, Contreras dominated opposing hitters in April, finishing 4-0 with a 1.45 ERA to earn American League Pitcher of the Month honors.
In five April starts, Contreras allowed just 24 hits and six runs over 37 1/3 innings. He is riding a 12-game regular-season winning streak dating back to last year, which equals the fourth-longest in club history. Jim Kaat won 12 straight for the White Sox from Sept. 4, 1974 through May 9, 1975.
Whereas Jon Garland burst to a rousing start in 2005, teaming with Mark Buehrle as a dynamic 1-2 punch in the rotation, it has been Contreras moving front and center through the opening month of this season for the first-place White Sox.
The signature outing of the month for Contreras came on April 17 when he pitched a one-hitter through seven innings in a win over Kansas City.
"The most important thing is we are winning and I'm going to do everything possible to help the team out," Contreras said. "Hopefully, I can carry it on into the playoffs."
Contreras was also the AL Pitcher of the Month last September, making him the first pitcher since Pedro Martinez (1999-2000) to finish one season and begin the next as the Pitcher of the Month.
The last pitcher to win consecutive Pitcher of the Month honors was Minnesota's Johan Santana, who did it in July, August and September of 2004.
The White Sox have had the Pitcher of the Month in April three of the last four years. Esteban Loaiza captured that honor in 2003 and Garland won it in 2005.
Contreras was 15-7 with a 3.61 ERA in 32 starts last year before winning three games in the playoffs. He can only hope his May performance emulates April.
"We are certainly pleased with where he is and where we are as a result of what he has done," White Sox general manager Kenny Williams said.
Robert Falkoff is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.