Cubs C Soto has torn meniscus

Chicago Cubs catcher Geovany Soto will have surgery to repair a torn meniscus in his left knee and will be out three to four weeks.

The Cubs made a roster move before Friday’s game with the White Sox, optioning struggling right-hander Chris Volstad to Triple-A Iowa and purchasing the contract of catcher Blake Lalli from the same club.

Volstad, acquired in the deal that sent Carlos Zambrano to the Marlins, was 0-6 with a 7.46 ERA in eight starts. The Cubs are expected to call up lefty Travis Wood to take Volstad’s place in the rotation and he could start Tuesday at Houston.

Soto is off to a slow start, batting .161 with three homers and six RBI this season. The 29-year-old catcher hit .228 with 17 homers and 54 RBI for Chicago last season. Wellington Castillo started for Soto on Thursday and will now be the No. 1 catcher.