The Giants signed a high-profile arm out of the Caribbean on Saturday, when they reached an agreement with Simon Mercedes of the Dominican Prospect League. Mercedes, an 18-year-old who signed for $400,000, pitched in the league's All-Star Game on Saturday, working two innings and striking out three batters in his brief stint.

A right-handed pitcher who works in the low 90's with his fastball, Mercedes became the second player from the DPL to sign this month and the 30th since the league's second season began three months ago. Right-handed pitcher Darwin Castillo signed with the Royals last week for $300,000. Mercedes is the 71st DPL player to sign since October of 2009.

The Giants have staked a lot on their scouting of young pitchers in recent years, and they won the 2010 World Series on the strength of a starting rotation that featured homegrown arms, in Tim Lincecum, Matt Cain and Jonathan Sanchez.

Mercedes, who will start out low in the team's farm system, has a chance to be another link in the chain.