Before the 2007 season, Antonelli was not considered to have much power potential after having zero home runs in over 200 professional at bats in . However, he hit 14 home runs in 82 games for High A Lake Elsinore, before moving up to Double A San Antonio Missions to finish the season. In 534 at-bats between the two levels, Antonelli finished with a slash line of .304/.404/.491 with 21 home runs and 25 stolen bases along with a 94/83 K/BB ratio. He won the Texas League Championship with the Missions in 2007.