Extra bases

• Outfielder Nate Schierholtz was released and will become a free agent by Friday. Schierholtz was designated for assignment on Aug. 6 after batting .192 in 99 games with six home runs, 10 doubles and 33 RBIs.

• The Cubs were encouraged by Felix Doubront's first rehab start with Triple-A Iowa. Doubront threw 80 pitches over four-plus innings on Tuesday night against Las Vegas. He has been on the disabled list since July 31 with a left calf strain.

"With him, he has to work his way back," Hoyer said. "We do look at it similarly to where [Jake] Arrieta was [last year]. [Doubront] is a guy who has had moments of success in the AL East. Getting his confidence and stuff back is important."

The left-hander will make at least one more start for Iowa.

• Cubs outfielder Justin Ruggiano did not start Wednesday because of some soreness in his right groin, but he was available to pinch-hit. Ruggiano was pulled from Tuesday's game after seven innings.

• To help Wrigley Field celebrate its 100th anniversary, American rock band O.A.R. will perform an Extra Innings Show as part of a free music event presented by Budweiser on Aug. 23 from 11 a.m. to 8 p.m. CT, in the Red and Purple Lots on the west side of the ballpark.

O.A.R. will take the stage for a 90-minute post-game set following the conclusion of the Cubs' Interleague game that day against the Orioles.

This summer, O.A.R released their eighth studio album, The Rockville LP, and recently played at the 2014 All-Star game in Minneapolis. Their song, "This Town," is played while the Cubs are introduced before home games.

The event is free to the general public and limited to a first-come, first-served basis.

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.