(CBS) The Chicago Cubs have designed often-erratic pitcher Carlos Marmol for assignment.

The 30-year-old Marmol went 2-4 with two saves and a 5.86 ERA in 31 relief appearances this season. He struck out 32 and walked 21 batters in 27.2 innings pitched, an average of 10.4 strikeouts and 6.8 walks per nine innings.

Cubs manager Dale Sveum shifted Marmol in and out of the closer role periodically throughout the season.

In eight seasons with the Cubs, Marmol, who is earning $9.8 million this season, went 23-32 with a 3.50 ERA in 483 appearances with the Cubs, 470 of the outings in relief.

The Cubs also released third baseman Ian Stewart, whose suspension for making derogatory comments about the organization on Twitter was upheld.

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