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06/30/09 3:01 PM ET

Astros' top pick adjusting to pro life

After signing quickly, Mier diving into action at Greeneville

Finding shortstops in the First-Year Player Draft who can stay at the position is tricky. Getting a young high school middle infielder with the defensive chops to stick is even tougher.

That's a big reason why Jiovanni Mier was so high on Draft boards and why the Astros were excited to nab him at No. 21 overall in the first round. The consensus among scouting directors was that Mier was probably the best pure shortstop in the class. So when Mier signed and began his career with Greeneville in the rookie-level Appalachian League on Saturday, being able to show his defensive acumen was high on Mier's early checklist.

"I haven't gotten an actual ground ball yet to throw over," said Mier, who's played in two games as of Tuesday. "We had a double-play ball [Sunday]. Well, I thought for sure it'd be a double play. The runners were really fast and they beat it out."

That's been the biggest adjustment for the 18-year-old in the early going -- the speed of the game. On both sides of the ball, Mier has been quick to realize that the tempo is just a little bit different than in his Southern California high school league.

"I knew it was going to be much faster, but it's a lot quicker than I expected," Mier said. "Everything is much faster. I'm coming from high school, so obviously the pitching is much harder, the runners are faster. You have to be on your toes.

"High school competition wasn't too bad, but it's a huge step to the pitchers, they're much more advanced. In high school, they're basically fastball, curve. Here, they've got everything else and they can do a lot more with their pitches."

Mier didn't waste too much time in showing that he has the ability to do something with those pitches in his debut. In his first professional at-bat, facing Danville lefty Jeff Lorick, he lined a single to left field and came around to score. He singled and scored again in the second inning. Though he went 0-for-3 in his second game, Mier can't complain about beginning his career 2-for-6 with three runs scored.

"It was exciting," Mier said about his debut. "It was my first at-bat and I wanted to do something good. It wasn't much, but it was exciting to be in front of the fans and such.

"You always want to go out and make a good first impression. I was happy to be able to do that and get my feet wet a little bit."

He's very pleased that he was able to do that so quickly after being drafted. There wasn't going to be any kind of long holdout or nasty negotiations once Mier got taken. He got his reported $1.358 million bonus, came to Houston for his physical and to meet and greet the big leaguers he hopes to one day join and then immediately headed to join his club in Greeneville.

"It was really important," Mier explained. "That was our goal coming into the Draft, get me signed and get me out there, get me as many at-bats as I could, get me acclimated to the Minor League season, so I can have a better chance heading into instructs, Spring Training and next year. I didn't want to waste time with anything. We did a good job getting signed as quickly as I could."

Eventually, Mier will get to show what he can do with the glove. He gained a reputation in high school with his good hands, range and above all else, his defensive instincts. He's not the fastest player, but he makes up for that with terrific positioning and anticipation. He's simply got a feel for playing the premium spot in the infield and goes about his business with a quiet confidence. Fans in Greeneville, and if all goes according to plan, eventually in Houston, will get to see all of it on display.

"I know I can stay there," Mier said. "There's still a lot to learn at that position as I progress. As I get older, I'm going to learn and it'll get easier."

Jonathan Mayo is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.