The Astros got some good news Tuesday when an MRI on All-Star catcher Jason Castro’s sprained right knee revealed no structural damage. Nonetheless, he needed to have a cyst drained near the medial collateral ligament area of the knee. “The cyst was interfering with my hamstring so they drained it,” Castro said. “So hopefully that should provide some relief.” Castro, who is arguably the Astros’ MVP this season, is optimistic about returning soon. “Yeah, it’s a day-to-day kind of thing,” he said. “I’m feeling OK. The more time we get away from what happened yesterday, the better it’s felt.” xxx It didn’t take long for Bo Porter to decide rookie [...]