#4 Alex Verdugo
Alex Verdugo is once again finding his name floated in trade rumors. He's in his final year of arbitration before hitting free agency, and coming off of a nightmare second half, likely has a much lower price tag than he did this time last season.
Verdugo brings balance to the Astros lineup as a lefty, and would seamlessly fill the role of Michael Brantley. He's never hit more than 13 home runs in a season, but is a doubles machine that rarely strikes out.
Verdugo was worth 9 DRS as a rightfielder last year, but also has experience as a left fielder, and for his career, has been worth 21 DRS in left.
Verdugo, like Gurriel, would help the Astros both offensively and defensively.
The farm system is getting more and more bare by the day, so it would be wise for the Astros to address their needs in free agency rather than via trade. If they are to make a trade, Verdugo is a target that would help them improve and that they could realistically meet the price tag for.