The Astros will pay each team $50,000 for Fields and Freiman, who must both remain in the Major Leagues for the entire 2013 season or be offered back to their respective former organizations.
Fields was drafted in the second round in 2007 by the Braves out of Georgia and returned to school and was selected in the first round (20th overall) the next year by the Mariners. He's had control problems, but Goldstein said he began to come around at the end of 2011.
"The arm is actually fresher than most guys his age, so that's something maybe works to our advantage," he said.
The Astros would have passed with their first pick of the second round had Freiman not been available, Goldstein said. Freiman is a 6-foot-7 right-handed power bat who wears out left-handed pitching and could feast on the Crawford Boxes in left field.
He could get time at designated hitter and first base next season, though the Astros may still try to add a veteran DH at some point.
Freiman, 25, hit .298 with 24 homers and 105 RBIs in 137 games at Double-A San Antonio (Padres) with 95 strikeouts in 581 plate appearances. He followed up his big season with San Antonio with a standout performance for Team Israel -- four of his five hits were home runs -- in the World Baseball Classic qualifier in September, where he played for manager Brad Ausmus.
"This is a guy who's worth taking a chance on, a guy we've like since his days at Duke," Goldstein said. "He was great in Arizona and played well for Israel as well. Right-handed guys with that kind of power are not normally available in the Rule 5. He destroys left-handed pitching, and he's a guy you give an opportunity to him in the spring and see what he can do."
Houston also took two players in the Minor League phase -- outfielder Michael Burgess from the Cubs and right-handed pitcher Cameron Lamb from the Giants.
Burgess, 24, hit .259 with 22 doubles, 10 homers, 43 RBIs and a .350 on-base percentage last season in 119 games with Double-A Tennessee. He owns a .252 average with 131 doubles, 18 triples, 102 homers, 388 RBIs and a .344 on-base percentage in 680 career Minor League games with the Nationals (2007-2010) and Chicago Cubs (2011-12) organizations.
Burgess, who was a favorite of manager Bo Porter, has raw power and good plate discipline and patience and is likely headed to Double-A.
Lamb, 23, went 2-1 with a 2.10 ERA last season in 12 appearances in the Arizona Fall League and with Class A Salem-Keizer. A native of Australia, he was originally signed by the Giants as a non-drafted free agent on Jan. 26, 2007. He is 11-10 with a 4.26 ERA and 150 strikeouts in 181 2/3 innings in his career.
Lamb has an average velocity fastball and has dropped his arm slot nearly to the side.
"He does two things we really like -- he doesn't walk anybody and he gets ground balls," Goldstein said. "Those two skills really appeal to us, and we decided to take a chance on him."