TROY, N.Y. — One pitch into his professional career, Mark Appel was watching his center fielder chase a triple that went over his head. Two pitches in, the Astros’ No. 1 pick in the draft was trailing. “Welcome to pro ball,” Appel said Friday. Twenty-six pitches in, he was safely back in the Tri-City ValleyCats dugout, having encountered some early rust and an aggressive opponent but more or less surviving his greatly anticipated debut. He nearly matched the prescribed limits of two innings and 30 pitches, throwing 19 in a rough first inning and seven in a smooth second. After 19-year-old Red Sox prospect Tzu-Wei Lin smacked one over center [...]