But on Wednesday, the Padres got their guy anyway, a player who has Minor League options and offers plus defense at shortstop, and can play elsewhere in the infield.
"In his college days, he was a really good defender," said general manager Josh Byrnes. "He has actually swung the bat pretty well in the Minor Leagues, but his strength is his defense."
Jackson hit .278 with a .352 on-base percentage in 2013 for the Cardinals' Triple-A affiliate. Jackson has 24 Major League at-bats over the last two seasons, collecting two hits.
Over his first five Minor League seasons in the St. Louis organization, Jackson has a .270 average.
Last season, the Padres -- who like Everth Cabrera's durability at shortstop -- used Pedro Ciriaco and later Ronny Cedeno when Cabrera was suspended for the final 50 games of the regular season for using performance enhancing drugs. This trade gives the club some coverage with a player who can handle the position.
Guzman became somewhat redundant when the team acquired outfielder Seth Smith recently in the deal that sent reliever Luke Gregerson to the A's.
Guzman, 29, hit .226 with nine home runs and 35 RBIs in 288 at-bats for the Padres last season and hit .259 with 23 home runs and 127 RBIs in 910 plate appearances with the Padres the last three seasons.
The Padres still have a full 40-man roster after the Guzman trade, meaning that when the team officially adds reliever Joaquin Benoit, who has agreed to a two-year deal with a buyout for 2016, they'll need to create a spot on the 40-man roster. However, the move won't be official until Benoit passes a physical.
Corey Brock is a reporter for MLB.com. Keep track of @FollowThePadres on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.