PITTSBURGH -- The Pittsburgh Steelers are excited about the growth of Drew Allar and how they can develop him into a star at the NFL level. The Penn State product was a third-round pick but has all the upside of an NFL starter, and head coach Mike McCarthy sees that, and is excited to work with it. "I think, like anything, I believe in first impressions," McCarthy said after the NFL Draft. "I've had a chance to watch him play, meet him at the Combine, and really, all the quarterbacks that came into the meeting room did very well. I liked everything about him. I think he's young. I think he's got a lot of room for growth. He's a young man that can throw the ball with the best of them, and that's a great starting point to have." That excitement isn't just in Pittsburgh, though. While Allar may be a third-round pick and a polarizing player coming out of college, he has one of the draft's strongest arms and best physical traits in the class.…