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7/2/2014 2:48 P.M. ET

Astros ink three top international prospects

Shortstop Sierra, right-hander Perez among Top 30 ranked available players

The Astros added a pair of highly touted Venezuelan teenagers to their system by signing shortstop Miguel Angel Sierra and right-handed pitcher Franklin Perez on Wednesday, the first day of the international signing period, according to an industry source.

Perez, who ranks No. 21 on MLB.com's Top 30 International Prospects list, and Sierra, who ranks No. 23, each received a $1 million signing bonus. It represents the most the Astros have spent on Venezuelan talent.

Additionally, the club signed catcher Brandon Benavente, who is also from Venezuela, for an estimated $250,000. The Astros are also targeting Dominican outfielder Ronny Rafael, ranked No. 20. General manager Jeff Luhnow said the team plans to be in the Dominican later this week.

"The Astros have a rich history of scouting and signing Major League players in Latin America, and a large part of that has been in Venezuela," Luhnow said. "By signing three excellent players today, the Astros are making a historically large investment in Venezuelan players that adds substantially to our prospect portfolio."

Perez has an explosive fastball that's been clocked at 93 mph but usually hovers in the 88- to 91-mph range. He also has an effective 12-6 curveball with late break, and he's getting a better feel for his changeup. He projects as a middle-of-the-rotation starter and appears to have the tools to reach his potential.

Scouts like Sierra's footwork and quick hands on defense. He has a line-drive swing to all fields and has a chance to hit for average with serviceable power in the future.

"When we discussed building our international program, we talked about wanting the Houston Astros to be Venezuela's team," director of international scouting Oz Ocampo said. "Under Andres Reiner, the Astros opened up the first baseball academy in Venezuela in 1989. Since then, our organization has produced 23 Major League players from Venezuela, including Johan Santana, Freddy Garcia, Carlos Guillen, Melvin Mora, Richard Hidalgo, Bobby Abreu, and Jose Altuve. Given the Astros' long and storied history in Venezuela, we wanted to again become the top destination for the very best Venezuelan talent every year."

In accordance with the Collective Bargaining Agreement, each team is allotted a $700,000 base and a bonus pool based on the team's record in 2013 for the international signing period. Houston's bonus pool total for this year's signing period is $5,015,400.

"We're not done yet," Luhnow said. "We're still moving on. There will be another signing out of Central America hopefully later this week."

Jesse Sanchez is a national reporter for MLB.com. Follow him on Twitter @JesseSanchezMLB. Mike Vernon is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.