Young has agreed to a one-year, $750,000 contract with the Phillies, Senior Vice President and General Manager Ruben Amaro Jr. announced today.
The contract includes performance bonuses.
"Delmon is an experienced major league bat who will add some depth to our relatively inexperienced outfield and another layer of competition for playing time there as well," said Amaro.
Young, 27, batted .267 with 27 doubles, 18 home runs and 74 RBI in 151 games for the Detroit Tigers last year.
In 13 postseason games, Young batted .313 with three home runs and a team-best nine RBI and was named MVP of the American League Championship Series.