At 6'3" 218 pounds, Hosey was originally drafted by the Cleveland Indians in the 19th round of the draft. He chose not to sign with the Indians, and was drafted again in the first round of the draft by the Giants, with whom he chose to sign.
Hosey spent less than four seasons in the minor leagues before making his major league debut on August 29, at the age of 23. Hosey was very strikeout prone; in 58 career major league at bats he struck out 16 times and walked only once. Hosey did not live up to his first-round draft pick status as he never appeared in more than 21 games in a season.
His final major league game was on September 15, . He last played professional baseball in 1998.