The Astros had acquired Jackson off outright waivers from the St. Louis Cardinals on Nov. 20. He played mostly shortstop and hit.278 with three home runs and 34 RBIs in 121 games for Triple-A Memphis in 2013.
He made his big league debut for the Cardinals in 2012 and played in 29 games in two seasons for St. Louis.
Guzman hit .226 with nine home runs and 35 RBIs in 126 games for the Padres last season. He spent parts of four seasons with San Diego.