Update: Castro will be sidelined the next few days due to tightness in his left hamstring, Carrie Muskat of MLB.com reports. "He's fine," manager Dale Sveum said. "It'll be two or three days, but basically it's minimal - there's more tightness. I don't think there's any pull. It just tightened up on him."
Recommendation: Castro played catch Thursday, so he's not completely incapacitated. Looks like Castro and the Cubs dodged a bullet.