Andrew Cashner and Josh Vitters, the Cubs' first-round picks in 2008 and '07, respectively, plus standout shortstop Starlin Castro are playing for the Mesa Solar Sox.
Cashner is expected to start Friday when the Solar Sox play at HoHoKam Park in Mesa, Ariz. He'll be joined on the roster by pitchers John Gaub, James Russell, and Blake Parker, who are all scheduled to throw Wednesday against Phoenix.
Cashner began the season at Class A Daytona, where he posted a 1.50 ERA in 12 starts, and was moved up to Double-A Tennessee in early July, where he went 3-4 with a 3.39 ERA in 12 starts. The right-hander struck out 41 in 58 1/3 innings.
Gaub, one of three pitchers the Cubs acquired from Cleveland in the Mark DeRosa trade, could challenge for a spot on the big league roster in 2010. The lefty was 3-1 with a 2.83 ERA in 26 games for Tennessee and compiled a 1.72 ERA in 26 games for Triple-A Iowa. Teams batted .172 against him.
Vitters batted .316 in 70 games with Class A Peoria and .238 in 50 games with Daytona. The third baseman was slowed by a hand injury.
Castro, 19, who played on the World team in the All-Star Futures Game, will be the youngest player in the AFL. This year, he batted .302 in 96 games at Class A Daytona and .288 in 31 games at Double-A Tennessee.
Catcher Welington Castillo also will be on the Solar Sox. He spent time with the big league team in Spring Training, and batted .232 in 95 games with Tennessee.
Bo Porter, who played for the Cubs and is currently a coach on the Florida Marlins, will manage the Mesa team, which will play its home games at HoHoKam Park, while Dennis Lewellyn, who has been a coach in the Cubs' system, will be the Solar Sox pitching coach.
Jeff Samardzija kicked off the winter ball season Friday when he started for Mexicali against Hermosillo in the first game of the Mexican Winter League. The right-hander gave up one run on three hits and two walks over four innings, striking out two, in Mexicali's 13-4 loss. Samardzija did not get a decision.
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.