DeShields, who had a physical Thursday in Houston and had his signing made official later in the day, was chosen by the Astros with the No. 8 overall pick in June's First-Year Player Draft.
"I'm really excited," DeShields said. "I'm glad everything is over with and finalized. I'm ready to get going."
It took more than two months for the Astros and DeShields to reach an agreement. DeShields will spend a week at the Astros' complex in Kissimmee, Fla., before reporting to rookie-league Greeneville to finish the season and make the transition to second base from the outfield.
"I want to get out there right away, but this summer is the first one I had off in 12 years," DeShields said. "I haven't played any baseball, so it's kind of weird. But I was glad I got the chance to stay at home because all my friends are going to college and I got to spend my last summer at home probably ever.
"That was good for me, but I've been real anxious and I had to wait. I waited long enough and it's finally over with."
DeShields is the son of longtime Major League player Delino DeShields, and dad was happy son will soon be officially an Astro.
"Glad to finally get the deal done," he said in a text message to MLB.com. "Looking forward to joining the Astros family."
DeShields, drafted out of Woodward Academy in College Park, Ga., will likely be spent to the Gulf Coast League for a few days before being shipped to begin his professional career at Greeneville. The Astros would like him to get at least 100 at-bats.
DeShields played outfield in high school, but the Astros drafted him as a second baseman and plan to put him at that position in the fall instructional league. He was the leadoff hitter for his private school and hit .415 and led the team in homers (nine), RBIs (40) and stolen bases (29).
Brian McTaggart is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.