Most of the impact players on the Houston Astros are home-grown talent, but they do have some key players that were acquired through trades and signed during free agency.
The current 40-man roster of the Houston Astros contains 5 players signed through free agency. These players include Charlie Morton, Josh Reddick, Hector Rondon, Tony Sipp, and Joe Smith.
15 players were either involved in trades or waiver claims by the Astros from another team. These players include Gerrit Cole, Chris Devenski, Evan Gattis, Marwin Gonzalez, Will Harris, Martin Maldonado, Jake Marisnick, Francis Martes, Collin McHugh, Brian McCann, Roberto Osuna, Brad Peacock, Ryan Pressly, Max Stassi, and Justin Verlander.
This leaves a whopping 20 home-grown players currently on the Astros 40-man roster. These players include Jose Altuve, Alex Bregman, Carlos Correa, J.D. Davis, Dean Deetz, Derek Fisher, Reymin Guduan, Yuli Gurriel, Josh James, Tony Kemp, Dallas Keuchel, Lance McCullers Jr., Cionel Perez, AJ Reed, Brady Rodgers, George Springer, Myles Straw, Kyle Tucker, Framber Valdez, and Tyler White.
Devenski, Gonzalez, and Martes have only ever suited up for the Astros at the MLB level. Perez had his initial free agent contract voided, but re-signed with the Astros again shortly after that occurred. As the Astros are the defending World Series Champions, having half of their 40-man roster as home-grown talent is very impressive.
Roster construction recap:
The four remaining AL teams in the MLB Playoffs rank in the following order from least to most regarding free agent signings on the roster: Yankees (4), Astros (5), Indians (9), and Red Sox (9).
Regarding all non-amateur signings or free agency signings, the teams rank in the following order from least to most: Astros (15), Red Sox (15), Indians (16), and Yankees (21).
Regarding the home-grown talent on each roster, the teams rank in the following order from least to most: Indians (15), Yankees (15), Red Sox (16), and Astros (20).