Cubs manager Dale Sveum met Friday with Theo Epstein, Cubs president of baseball operations, general manager Jed Hoyer and pitching coach Chris Bosio to discuss Volstad's future after his outing Thursday.
The right-hander is 0-6 after a loss to the Phillies and winless in his last 19 starts, dating back to last July. On Thursday, he gave up four runs on six hits over two innings. It was his shortest outing since Aug. 28, 2009, when he lasted 1 2/3 innings against the Padres.
"I'm not going to say it's a small thing," Sveum said. "There's more to it than that. The easiest thing is it's probably a confidence factor. We all saw the confidence he showed in Spring Training and the dominance he had there with the location and the movement he had on the sinker and using the sinker in Spring Training. It's a lot more confidence than mechanics than anything like that."
Volstad, acquired from the Marlins for Carlos Zambrano, had one option left. He will start for Iowa. The Cubs added catcher Blake Lalli from Iowa on Friday, selecting his contract, and the 40-man roster now is at 40.
Lalli, 29, has a .298 career batting average in the Minor Leagues. He also can help in a pinch out of the bullpen. He's made 18 career relief appearances, going 1-1 with a 3.21 ERA.
A left-handed batter, Lalli was a non-roster invitee to Major League Spring Training for the second time this year. He made his Major League debut on Friday, entering the game defensively in the ninth.
Travis Wood, acquired this offseason from the Reds in the Sean Marshall deal, picked up a win Thursday for Triple-A Iowa, giving up two runs on five hits over seven innings. Wood will fill Volstad's spot Tuesday against the Astros in Houston.
The Cubs are short-handed at catcher because of Geovany Soto's knee injury. Lalli is the fourth catcher to be used this season. Backup Steve Clevenger is on the disabled list with a rib-cage injury. Welington Castillo started Friday.