The first person to see Stephen Piscotty lying unconscious, blood trickling from his mouth, in left-center field Monday night at PNC Park after a vicious collision was also one of the last to see him a few hours later at the hospital. So Peter Bourjos had perhaps the best description of his recovery. “Amazing turnaround,” Bourjos said. “Pretty amazing.” Piscotty was released Tuesday afternoon from Allegheny General Hospital having gone through a second wave of tests that morning. He was diagnosed with a concussion, general manager John Mozeliak said, but extensive scans of his head, face and neck revealed no fractures, and an MRI scan taken Tuesday morning did not show any additional trauma. He was back at the team hotel resting as dismal weather postponed Tuesday night’s game between Pittsburgh and the Cardinals and forced a doubleheader Wednesday. The view from doctors who saw Piscotty was so optimistic that Mozeliak said it’s possible the rookie could play before the end of the regular season, which is Sunday. “I had no idea what to expect when we got (to the hospital),” Mozeliak said. “And then to see him with the energy and the fact that he had an appetite. He was willing to talk about the events of the evening — really amazing. … I think the good news is he will probably play again in the regular season. There’s no reason to speculate (when) at this moment. The ultimate decision will be how he feels and what he wants to do as well. The game is about feel and timing and if it makes sense to get him in and he feels up to it, I think we’ll do that.” With a concussion, Piscotty does enter Major League Baseball’s prescribed protocols. He will have to pass a test Wednesday in Pittsburgh or Thursday in Atlanta before being cleared to return to the lineup. He went through a series of neurological exams Tuesday and passed “with flying colors,” manager Mike Matheny said.