Extra bases

• Castillo, on the disabled list since June 2 with right rib cage inflammation, will begin a rehab assignment with Triple-A Iowa on Thursday. Castillo had been working out at the Cubs' complex in Mesa, Ariz.

• With the off-day Thursday, the Cubs will not change their rotation, and just give everyone an extra day. Edwin Jackson will open the three-game series Friday against the Pirates.

• In addition to Bryant joining Triple-A Iowa, the Cubs announced right-handed pitchers Arodys Vizcaino and Armando Rivero also were promoted to the Minor League team. Vizcaino, who is coming back from Tommy John surgery, compiled a 2.63 ERA in 14 games at Double-A Tennessee. Rivero had a 1.56 ERA in 26 games with the Smokies and had 10 saves.

Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.