A sixth round selection in 2008 out of Cy-Fair high school, Astros left fielder Robbie Grossman was taught plate discipline early.

He started his career with the Pirates, who traded him to the Astros in July 2012 as part of the Wandy Rodriguez deal. (The Astros are on the hook for $5.5 million of Rodriguez’s salary this season, so at least they’re getting a return on that investment.)

“I think it helped me switch hitting as a young kid,” Grossman said. “I knew that I could hit from either side, what were my strengths and weaknesses. And I learned what I could really do with certain pitches and what I can’t.”

Grossman was born in San Diego but grew up in Cypress, and he always had a good eye.

Still, it wasn’t until he arrived in pro ball with the Pirates that the importance of plate discipline was fully hammered home.

“I was with Pittsburgh before and they were big on it and did a lot of drills,” Grossman said Wednesday, before the Astros’ final spring training game of the year. “They emphasized that. It was part of my game I always had. It helps me tremendously.”

That’s not an overstatement.

With fewer than 300 plate appearances in the majors, Grossman, 24, is poised to be the Astros’ No. 2 hitter in 2014.

The sophomore was always expected to win an opening day job in left field after a fine half season in the majors in 2013. But he wasn’t widely expected to be at the top of the order.

All offseason and even last week, Astros manager Bo Porter talked of his excitement for Jose Altuve as the team’s No. 2 hitter. Dexter Fowler would be leadoff and Jason Castro would bat third.