The Houston Astros signed infielder Koby Clemens, the son of seven-time Cy Young award winner Roger Clemens, on Thursday. Koby, Houston's eight-round selection in the most recent draft, had signed a letter of intent to play at the University of Texas. Instead, he will begin his professional career with the Astros' rookie league affiliate -- the Greenville Astros. The younger Clemens, who pitched and played third base for Memorial (TX) High School, batted .523 with 10 home runs, 14 doubles, a triple and 55 RBI this year. He posted a .953 slugging percentage and .617 on-base percentage, and scored 39 runs with five stolen bases. On the mound, he finished 8-3 with a 3.17 ERA and 86 strikeouts, holding opposing batters to a .203 average. He tossed three no-hitters and four complete games, and was named the Most Valuable Player for District 18-5A. In another move by Houston on Thursday, the Astros recalled pitcher Ezequiel Astacio from Triple-A Round Rock. To make room on the roster, the club optioned pitcher Travis Driskill to Round Rock.